[PATCH 0/2] spufs: mmap fixes and updates

[PATCH 0/2] spufs: mmap fixes and updates

[Benjamin Herrenschmidt]

This is a new version of the spufs patch removing dependency
on struct page along with a bugfix for some serious bitrot that
happened in spufs mmap facility lately.

I'm not reposting the 2 VM patches that this depends on as they
haven't changed and are queued up with Andrew

Ben.

[PATCH 1/2] spufs: remove need for struct page for SPEs

[Benjamin Herrenschmidt]

This patch removes the need for struct page for SPE local store
and registers from spufs. It also makes the locking much more
obvious and no longer relying on the truncate logic black magic
for protecting against races between unmap_mapping_range() and
new pages faulted in. It does so by switching to a nopfn() handler
and using the new vm_insert_pfn() to setup the PTEs itself while
holding a lock on the SPE.

The nice thing is that this patch actually removes a lot more code
than it adds :-)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

 Kconfig                         |    2

Index: linux-cell/arch/powerpc/platforms/cell/spu_priv1_mmio.c
===================================================================
--- linux-cell.orig/arch/powerpc/platforms/cell/spu_priv1_mmio.c	2007-02-09 12:48:56.000000000 +1100
+++ linux-cell/arch/powerpc/platforms/cell/spu_priv1_mmio.c	2007-02-09 14:49:21.000000000 +1100
@@ -57,37 +57,6 @@ struct device_node *spu_devnode(struct s
 
 EXPORT_SYMBOL_GPL(spu_devnode);
 
-static int __init cell_spuprop_present(struct spu *spu, struct device_node *spe,
-		const char *prop)
-{
-	const struct address_prop {
-		unsigned long address;
-		unsigned int len;
-	} __attribute__((packed)) *p;
-	int proplen;
-
-	unsigned long start_pfn, nr_pages;
-	struct pglist_data *pgdata;
-	struct zone *zone;
-	int ret;
-
-	p = get_property(spe, prop, &proplen);
-	WARN_ON(proplen != sizeof (*p));
-
-	start_pfn = p->address >> PAGE_SHIFT;
-	nr_pages = ((unsigned long)p->len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-
-	pgdata = NODE_DATA(spu->node);
-	zone = pgdata->node_zones;
-
-	/* XXX rethink locking here */
-	mutex_lock(&add_spumem_mutex);
-	ret = __add_pages(zone, start_pfn, nr_pages);
-	mutex_unlock(&add_spumem_mutex);
-
-	return ret;
-}
-
 static void __iomem * __init map_spe_prop(struct spu *spu,
 		struct device_node *n, const char *name)
 {
@@ -98,23 +67,13 @@ static void __iomem * __init map_spe_pro
 
 	const void *p;
 	int proplen;
-	void __iomem *ret = NULL;
-	int err = 0;
 
 	p = get_property(n, name, &proplen);
 	if (proplen != sizeof (struct address_prop))
 		return NULL;
 
 	prop = p;
-
-	err = cell_spuprop_present(spu, n, name);
-	if (err && (err != -EEXIST))
-		goto out;
-
-	ret = ioremap(prop->address, prop->len);
-
- out:
-	return ret;
+	return ioremap(prop->address, prop->len);
 }
 
 static void spu_unmap(struct spu *spu)
@@ -239,37 +198,21 @@ static int spu_map_resource(struct spu *
 			    void __iomem** virt, unsigned long *phys)
 {
 	struct device_node *np = spu_get_pdata(spu)->devnode;
-	unsigned long start_pfn, nr_pages;
-	struct pglist_data *pgdata;
-	struct zone *zone;
 	struct resource resource = { };
 	unsigned long len;
 	int ret;
 
 	ret = of_address_to_resource(np, nr, &resource);
 	if (ret)
-		goto out;
+		return ret;
 
 	if (phys)
 		*phys = resource.start;
 	len = resource.end - resource.start + 1;
 	*virt = ioremap(resource.start, len);
 	if (!*virt)
-		ret = -EINVAL;
-
-	start_pfn = resource.start >> PAGE_SHIFT;
-	nr_pages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-
-	pgdata = NODE_DATA(spu->node);
-	zone = pgdata->node_zones;
-
-	/* XXX rethink locking here */
-	mutex_lock(&add_spumem_mutex);
-	ret = __add_pages(zone, start_pfn, nr_pages);
-	mutex_unlock(&add_spumem_mutex);
-
-out:
-	return ret;
+		return -EINVAL;
+	return 0;
 }
 
 static int __init spu_map_device(struct spu *spu)
Index: linux-cell/arch/powerpc/platforms/cell/spufs/file.c
===================================================================
--- linux-cell.orig/arch/powerpc/platforms/cell/spufs/file.c	2007-02-09 12:48:56.000000000 +1100
+++ linux-cell/arch/powerpc/platforms/cell/spufs/file.c	2007-02-09 14:58:57.000000000 +1100
@@ -95,14 +95,12 @@ spufs_mem_write(struct file *file, const
 	return ret;
 }
 
-static struct page *
-spufs_mem_mmap_nopage(struct vm_area_struct *vma,
-		      unsigned long address, int *type)
+static unsigned long spufs_mem_mmap_nopfn(struct vm_area_struct *vma,
+					  unsigned long address)
 {
-	struct page *page = NOPAGE_SIGBUS;
-
 	struct spu_context *ctx = vma->vm_file->private_data;
-	unsigned long offset = address - vma->vm_start;
+	unsigned long pfn, offset = address - vma->vm_start;
+
 	offset += vma->vm_pgoff << PAGE_SHIFT;
 
 	spu_acquire(ctx);
@@ -110,24 +108,22 @@ spufs_mem_mmap_nopage(struct vm_area_str
 	if (ctx->state == SPU_STATE_SAVED) {
 		vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
 							& ~_PAGE_NO_CACHE);
-		page = vmalloc_to_page(ctx->csa.lscsa->ls + offset);
+		pfn = vmalloc_to_pfn(ctx->csa.lscsa->ls + offset);
 	} else {
 		vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
-							| _PAGE_NO_CACHE);
-		page = pfn_to_page((ctx->spu->local_store_phys + offset)
-				   >> PAGE_SHIFT);
+					     | _PAGE_NO_CACHE);
+		pfn = (ctx->spu->local_store_phys + offset) >> PAGE_SHIFT;
 	}
-	spu_release(ctx);
+	vm_insert_pfn(vma, address, pfn);
 
-	if (type)
-		*type = VM_FAULT_MINOR;
+	spu_release(ctx);
 
-	page_cache_get(page);
-	return page;
+	return NOPFN_REFAULT;
 }
 
+
 static struct vm_operations_struct spufs_mem_mmap_vmops = {
-	.nopage = spufs_mem_mmap_nopage,
+	.nopfn = spufs_mem_mmap_nopfn,
 };
 
 static int
@@ -136,7 +132,7 @@ spufs_mem_mmap(struct file *file, struct
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
-	vma->vm_flags |= VM_IO;
+	vma->vm_flags |= VM_IO | VM_PFNMAP;
 	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
 				     | _PAGE_NO_CACHE);
 
@@ -152,49 +148,42 @@ static struct file_operations spufs_mem_
 	.mmap    = spufs_mem_mmap,
 };
 
-static struct page *spufs_ps_nopage(struct vm_area_struct *vma,
+static unsigned long spufs_ps_nopfn(struct vm_area_struct *vma,
 				    unsigned long address,
-				    int *type, unsigned long ps_offs,
+				    unsigned long ps_offs,
 				    unsigned long ps_size)
 {
-	struct page *page = NOPAGE_SIGBUS;
-	int fault_type = VM_FAULT_SIGBUS;
 	struct spu_context *ctx = vma->vm_file->private_data;
-	unsigned long offset = address - vma->vm_start;
-	unsigned long area;
+	unsigned long area, offset = address - vma->vm_start;
 	int ret;
 
 	offset += vma->vm_pgoff << PAGE_SHIFT;
 	if (offset >= ps_size)
-		goto out;
+		return NOPFN_SIGBUS;
 
+	/* error here usually means a signal.. we might want to test
+	 * the error code more precisely though
+	 */
 	ret = spu_acquire_runnable(ctx);
 	if (ret)
-		goto out;
+		return NOPFN_REFAULT;
 
 	area = ctx->spu->problem_phys + ps_offs;
-	page = pfn_to_page((area + offset) >> PAGE_SHIFT);
-	fault_type = VM_FAULT_MINOR;
-	page_cache_get(page);
-
+	vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);
 	spu_release(ctx);
 
-      out:
-	if (type)
-		*type = fault_type;
-
-	return page;
+	return NOPFN_REFAULT;
 }
 
 #if SPUFS_MMAP_4K
-static struct page *spufs_cntl_mmap_nopage(struct vm_area_struct *vma,
-					   unsigned long address, int *type)
+static unsigned long spufs_cntl_mmap_nopfn(struct vm_area_struct *vma,
+					   unsigned long address)
 {
-	return spufs_ps_nopage(vma, address, type, 0x4000, 0x1000);
+	return spufs_ps_nopfn(vma, address, 0x4000, 0x1000);
 }
 
 static struct vm_operations_struct spufs_cntl_mmap_vmops = {
-	.nopage = spufs_cntl_mmap_nopage,
+	.nopfn = spufs_cntl_mmap_nopfn,
 };
 
 /*
@@ -205,7 +194,7 @@ static int spufs_cntl_mmap(struct file *
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
-	vma->vm_flags |= VM_IO;
+	vma->vm_flags |= VM_IO | VM_PFNMAP;
 	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
 				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
 
@@ -791,23 +780,23 @@ static ssize_t spufs_signal1_write(struc
 	return 4;
 }
 
-static struct page *spufs_signal1_mmap_nopage(struct vm_area_struct *vma,
-					      unsigned long address, int *type)
+static unsigned long spufs_signal1_mmap_nopfn(struct vm_area_struct *vma,
+					      unsigned long address)
 {
 #if PAGE_SIZE == 0x1000
-	return spufs_ps_nopage(vma, address, type, 0x14000, 0x1000);
+	return spufs_ps_nopfn(vma, address, 0x14000, 0x1000);
 #elif PAGE_SIZE == 0x10000
 	/* For 64k pages, both signal1 and signal2 can be used to mmap the whole
 	 * signal 1 and 2 area
 	 */
-	return spufs_ps_nopage(vma, address, type, 0x10000, 0x10000);
+	return spufs_ps_nopfn(vma, address, 0x10000, 0x10000);
 #else
 #error unsupported page size
 #endif
 }
 
 static struct vm_operations_struct spufs_signal1_mmap_vmops = {
-	.nopage = spufs_signal1_mmap_nopage,
+	.nopfn = spufs_signal1_mmap_nopfn,
 };
 
 static int spufs_signal1_mmap(struct file *file, struct vm_area_struct *vma)
@@ -815,7 +804,7 @@ static int spufs_signal1_mmap(struct fil
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
-	vma->vm_flags |= VM_IO;
+	vma->vm_flags |= VM_IO | VM_PFNMAP;
 	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
 				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
 
@@ -899,23 +888,23 @@ static ssize_t spufs_signal2_write(struc
 }
 
 #if SPUFS_MMAP_4K
-static struct page *spufs_signal2_mmap_nopage(struct vm_area_struct *vma,
-					      unsigned long address, int *type)
+static unsigned long spufs_signal2_mmap_nopfn(struct vm_area_struct *vma,
+					      unsigned long address)
 {
 #if PAGE_SIZE == 0x1000
-	return spufs_ps_nopage(vma, address, type, 0x1c000, 0x1000);
+	return spufs_ps_nopfn(vma, address, 0x1c000, 0x1000);
 #elif PAGE_SIZE == 0x10000
 	/* For 64k pages, both signal1 and signal2 can be used to mmap the whole
 	 * signal 1 and 2 area
 	 */
-	return spufs_ps_nopage(vma, address, type, 0x10000, 0x10000);
+	return spufs_ps_nopfn(vma, address, 0x10000, 0x10000);
 #else
 #error unsupported page size
 #endif
 }
 
 static struct vm_operations_struct spufs_signal2_mmap_vmops = {
-	.nopage = spufs_signal2_mmap_nopage,
+	.nopfn = spufs_signal2_mmap_nopfn,
 };
 
 static int spufs_signal2_mmap(struct file *file, struct vm_area_struct *vma)
@@ -923,7 +912,7 @@ static int spufs_signal2_mmap(struct fil
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
-	vma->vm_flags |= VM_IO;
+	vma->vm_flags |= VM_IO | VM_PFNMAP;
 	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
 				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
 
@@ -1000,14 +989,14 @@ DEFINE_SIMPLE_ATTRIBUTE(spufs_signal2_ty
 					spufs_signal2_type_set, "%llu");
 
 #if SPUFS_MMAP_4K
-static struct page *spufs_mss_mmap_nopage(struct vm_area_struct *vma,
-					   unsigned long address, int *type)
+static unsigned long spufs_mss_mmap_nopfn(struct vm_area_struct *vma,
+					  unsigned long address)
 {
-	return spufs_ps_nopage(vma, address, type, 0x0000, 0x1000);
+	return spufs_ps_nopfn(vma, address, 0x0000, 0x1000);
 }
 
 static struct vm_operations_struct spufs_mss_mmap_vmops = {
-	.nopage = spufs_mss_mmap_nopage,
+	.nopfn = spufs_mss_mmap_nopfn,
 };
 
 /*
@@ -1018,7 +1007,7 @@ static int spufs_mss_mmap(struct file *f
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
-	vma->vm_flags |= VM_IO;
+	vma->vm_flags |= VM_IO | VM_PFNMAP;
 	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
 				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
 
@@ -1042,14 +1031,14 @@ static struct file_operations spufs_mss_
 	.mmap	 = spufs_mss_mmap,
 };
 
-static struct page *spufs_psmap_mmap_nopage(struct vm_area_struct *vma,
-					   unsigned long address, int *type)
+static unsigned long spufs_psmap_mmap_nopfn(struct vm_area_struct *vma,
+					    unsigned long address)
 {
-	return spufs_ps_nopage(vma, address, type, 0x0000, 0x20000);
+	return spufs_ps_nopfn(vma, address, 0x0000, 0x20000);
 }
 
 static struct vm_operations_struct spufs_psmap_mmap_vmops = {
-	.nopage = spufs_psmap_mmap_nopage,
+	.nopfn = spufs_psmap_mmap_nopfn,
 };
 
 /*
@@ -1060,7 +1049,7 @@ static int spufs_psmap_mmap(struct file 
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
-	vma->vm_flags |= VM_IO;
+	vma->vm_flags |= VM_IO | VM_PFNMAP;
 	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
 				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
 
@@ -1083,14 +1072,14 @@ static struct file_operations spufs_psma
 
 
 #if SPUFS_MMAP_4K
-static struct page *spufs_mfc_mmap_nopage(struct vm_area_struct *vma,
-					   unsigned long address, int *type)
+static unsigned long spufs_mfc_mmap_nopfn(struct vm_area_struct *vma,
+					  unsigned long address)
 {
-	return spufs_ps_nopage(vma, address, type, 0x3000, 0x1000);
+	return spufs_ps_nopfn(vma, address, 0x3000, 0x1000);
 }
 
 static struct vm_operations_struct spufs_mfc_mmap_vmops = {
-	.nopage = spufs_mfc_mmap_nopage,
+	.nopfn = spufs_mfc_mmap_nopfn,
 };
 
 /*
@@ -1101,7 +1090,7 @@ static int spufs_mfc_mmap(struct file *f
 	if (!(vma->vm_flags & VM_SHARED))
 		return -EINVAL;
 
-	vma->vm_flags |= VM_IO;
+	vma->vm_flags |= VM_IO | VM_PFNMAP;
 	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
 				     | _PAGE_NO_CACHE | _PAGE_GUARDED);
 
Index: linux-cell/arch/powerpc/Kconfig
===================================================================
--- linux-cell.orig/arch/powerpc/Kconfig	2007-02-09 12:48:56.000000000 +1100
+++ linux-cell/arch/powerpc/Kconfig	2007-02-09 14:49:21.000000000 +1100
@@ -832,7 +832,7 @@ config ARCH_SPARSEMEM_ENABLE
 
 config ARCH_SPARSEMEM_DEFAULT
 	def_bool y
-	depends on (SMP && PPC_PSERIES) || PPC_CELL
+	depends on (SMP && PPC_PSERIES) || PPC_PS3
 
 config ARCH_POPULATES_NODE_MAP
 	def_bool y

[PATCH 2/2] spufs: Fix bitrot of the SPU mmap facility

[Benjamin Herrenschmidt]

It looks like we've had some serious bitrot there mostly due to tracking
of address_space's of mmap'ed files getting out of sync with the actual
mmap code. The mfc, mss and psmap were not tracked properly and thus
not invalidated on context switches (oops !)

Note that I kept the various file->f_mapping = inode->i_mapping;
assignments that were done in the other open() routines though it's
unclear to me wether those are really necessary as I think the generic
open code already does that but then, I'm not that familiar with
filesystem foo. Another improvement we might want to do is assign
those to the varioux ctx-> fields at mmap time instead of file open/close
time.

I also added some smp_wmb's after assigning the ctx-> fields to make sure
they are visible to other CPUs. I don't think this is really necessary as
I suspect locking in the fs layer will make that happen anyway but better
safe than sorry.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

 arch/powerpc/platforms/cell/spufs/context.c |   12 ++++++++----
 arch/powerpc/platforms/cell/spufs/file.c    |   15 +++++++++++++++
 arch/powerpc/platforms/cell/spufs/spufs.h   |    2 ++
 3 files changed, 25 insertions(+), 4 deletions(-)

Index: linux-cell/arch/powerpc/platforms/cell/spufs/context.c
===================================================================
--- linux-cell.orig/arch/powerpc/platforms/cell/spufs/context.c	2007-02-09 15:47:28.000000000 +1100
+++ linux-cell/arch/powerpc/platforms/cell/spufs/context.c	2007-02-09 15:48:27.000000000 +1100
@@ -111,13 +111,17 @@ void spu_unmap_mappings(struct spu_conte
 	if (ctx->local_store)
 		unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1);
 	if (ctx->mfc)
-		unmap_mapping_range(ctx->mfc, 0, 0x4000, 1);
+		unmap_mapping_range(ctx->mfc, 0, 0x1000, 1);
 	if (ctx->cntl)
-		unmap_mapping_range(ctx->cntl, 0, 0x4000, 1);
+		unmap_mapping_range(ctx->cntl, 0, 0x1000, 1);
 	if (ctx->signal1)
-		unmap_mapping_range(ctx->signal1, 0, 0x4000, 1);
+		unmap_mapping_range(ctx->signal1, 0, PAGE_SIZE, 1);
 	if (ctx->signal2)
-		unmap_mapping_range(ctx->signal2, 0, 0x4000, 1);
+		unmap_mapping_range(ctx->signal2, 0, PAGE_SIZE, 1);
+	if (ctx->mss)
+		unmap_mapping_range(ctx->mss, 0, 0x1000, 1);
+	if (ctx->psmap)
+		unmap_mapping_range(ctx->psmap, 0, 0x20000, 1);
 }
 
 int spu_acquire_exclusive(struct spu_context *ctx)
Index: linux-cell/arch/powerpc/platforms/cell/spufs/file.c
===================================================================
--- linux-cell.orig/arch/powerpc/platforms/cell/spufs/file.c	2007-02-09 15:47:28.000000000 +1100
+++ linux-cell/arch/powerpc/platforms/cell/spufs/file.c	2007-02-09 15:53:54.000000000 +1100
@@ -47,6 +47,7 @@ spufs_mem_open(struct inode *inode, stru
 	file->private_data = ctx;
 	file->f_mapping = inode->i_mapping;
 	ctx->local_store = inode->i_mapping;
+	smp_wmb();
 	return 0;
 }
 
@@ -234,6 +235,7 @@ static int spufs_cntl_open(struct inode 
 	file->private_data = ctx;
 	file->f_mapping = inode->i_mapping;
 	ctx->cntl = inode->i_mapping;
+	smp_wmb();
 	return simple_attr_open(inode, file, spufs_cntl_get,
 					spufs_cntl_set, "0x%08lx");
 }
@@ -719,6 +721,7 @@ static int spufs_signal1_open(struct ino
 	file->private_data = ctx;
 	file->f_mapping = inode->i_mapping;
 	ctx->signal1 = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -826,6 +829,7 @@ static int spufs_signal2_open(struct ino
 	file->private_data = ctx;
 	file->f_mapping = inode->i_mapping;
 	ctx->signal2 = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1021,8 +1025,12 @@ static int spufs_mss_mmap(struct file *f
 static int spufs_mss_open(struct inode *inode, struct file *file)
 {
 	struct spufs_inode_info *i = SPUFS_I(inode);
+	struct spu_context *ctx = i->i_ctx;
 
 	file->private_data = i->i_ctx;
+	file->f_mapping = inode->i_mapping;
+	ctx->mss = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1060,8 +1068,12 @@ static int spufs_psmap_mmap(struct file 
 static int spufs_psmap_open(struct inode *inode, struct file *file)
 {
 	struct spufs_inode_info *i = SPUFS_I(inode);
+	struct spu_context *ctx = i->i_ctx;
 
 	file->private_data = i->i_ctx;
+	file->f_mapping = inode->i_mapping;
+	ctx->psmap = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1114,6 +1126,9 @@ static int spufs_mfc_open(struct inode *
 		return -EBUSY;
 
 	file->private_data = ctx;
+	file->f_mapping = inode->i_mapping;
+	ctx->mfc = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
Index: linux-cell/arch/powerpc/platforms/cell/spufs/spufs.h
===================================================================
--- linux-cell.orig/arch/powerpc/platforms/cell/spufs/spufs.h	2007-02-09 15:47:28.000000000 +1100
+++ linux-cell/arch/powerpc/platforms/cell/spufs/spufs.h	2007-02-09 15:48:15.000000000 +1100
@@ -51,6 +51,8 @@ struct spu_context {
 	struct address_space *cntl; 	   /* 'control' area mappings. */
 	struct address_space *signal1; 	   /* 'signal1' area mappings. */
 	struct address_space *signal2; 	   /* 'signal2' area mappings. */
+	struct address_space *mss; 	   /* 'mss' area mappings. */
+	struct address_space *psmap; 	   /* 'psmap' area mappings. */
 	u64 object_id;		   /* user space pointer for oprofile */
 
 	enum { SPU_STATE_RUNNABLE, SPU_STATE_SAVED } state;

[PATCH] spufs: Fix bitrot of the SPU mmap facility (#2)

[Benjamin Herrenschmidt]

spufs: Fix bitrot of the SPU mmap facility

It looks like we've had some serious bitrot there mostly due to tracking
of address_space's of mmap'ed files getting out of sync with the actual
mmap code. The mfc, mss and psmap were not tracked properly and thus
not invalidated on context switches (oops !)

I also removed the various file->f_mapping = inode->i_mapping;
assignments that were done in the other open() routines since that
is already done for us by __dentry_open.

One improvement we might want to do later is to assign the various
ctx-> fields at mmap time instead of file open/close time so that we
don't call unmap_mapping_range() on thing that have not been mmap'ed

Finally, I added some smp_wmb's after assigning the ctx-> fields to make
sure they are visible to other CPUs. I don't think this is really
necessary as I suspect locking in the fs layer will make that happen
anyway but better safe than sorry.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

New version of that patch removing the f_mapping assignment.

Index: linux-cell/arch/powerpc/platforms/cell/spufs/context.c
===================================================================
--- linux-cell.orig/arch/powerpc/platforms/cell/spufs/context.c	2007-02-09 15:47:28.000000000 +1100
+++ linux-cell/arch/powerpc/platforms/cell/spufs/context.c	2007-02-09 15:48:27.000000000 +1100
@@ -111,13 +111,17 @@ void spu_unmap_mappings(struct spu_conte
 	if (ctx->local_store)
 		unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1);
 	if (ctx->mfc)
-		unmap_mapping_range(ctx->mfc, 0, 0x4000, 1);
+		unmap_mapping_range(ctx->mfc, 0, 0x1000, 1);
 	if (ctx->cntl)
-		unmap_mapping_range(ctx->cntl, 0, 0x4000, 1);
+		unmap_mapping_range(ctx->cntl, 0, 0x1000, 1);
 	if (ctx->signal1)
-		unmap_mapping_range(ctx->signal1, 0, 0x4000, 1);
+		unmap_mapping_range(ctx->signal1, 0, PAGE_SIZE, 1);
 	if (ctx->signal2)
-		unmap_mapping_range(ctx->signal2, 0, 0x4000, 1);
+		unmap_mapping_range(ctx->signal2, 0, PAGE_SIZE, 1);
+	if (ctx->mss)
+		unmap_mapping_range(ctx->mss, 0, 0x1000, 1);
+	if (ctx->psmap)
+		unmap_mapping_range(ctx->psmap, 0, 0x20000, 1);
 }
 
 int spu_acquire_exclusive(struct spu_context *ctx)
Index: linux-cell/arch/powerpc/platforms/cell/spufs/file.c
===================================================================
--- linux-cell.orig/arch/powerpc/platforms/cell/spufs/file.c	2007-02-09 15:47:28.000000000 +1100
+++ linux-cell/arch/powerpc/platforms/cell/spufs/file.c	2007-02-09 16:29:33.000000000 +1100
@@ -45,8 +45,8 @@ spufs_mem_open(struct inode *inode, stru
 	struct spufs_inode_info *i = SPUFS_I(inode);
 	struct spu_context *ctx = i->i_ctx;
 	file->private_data = ctx;
-	file->f_mapping = inode->i_mapping;
 	ctx->local_store = inode->i_mapping;
+	smp_wmb();
 	return 0;
 }
 
@@ -232,8 +232,8 @@ static int spufs_cntl_open(struct inode 
 	struct spu_context *ctx = i->i_ctx;
 
 	file->private_data = ctx;
-	file->f_mapping = inode->i_mapping;
 	ctx->cntl = inode->i_mapping;
+	smp_wmb();
 	return simple_attr_open(inode, file, spufs_cntl_get,
 					spufs_cntl_set, "0x%08lx");
 }
@@ -717,8 +717,8 @@ static int spufs_signal1_open(struct ino
 	struct spufs_inode_info *i = SPUFS_I(inode);
 	struct spu_context *ctx = i->i_ctx;
 	file->private_data = ctx;
-	file->f_mapping = inode->i_mapping;
 	ctx->signal1 = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -824,8 +824,8 @@ static int spufs_signal2_open(struct ino
 	struct spufs_inode_info *i = SPUFS_I(inode);
 	struct spu_context *ctx = i->i_ctx;
 	file->private_data = ctx;
-	file->f_mapping = inode->i_mapping;
 	ctx->signal2 = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1021,8 +1021,11 @@ static int spufs_mss_mmap(struct file *f
 static int spufs_mss_open(struct inode *inode, struct file *file)
 {
 	struct spufs_inode_info *i = SPUFS_I(inode);
+	struct spu_context *ctx = i->i_ctx;
 
 	file->private_data = i->i_ctx;
+	ctx->mss = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1060,8 +1063,11 @@ static int spufs_psmap_mmap(struct file 
 static int spufs_psmap_open(struct inode *inode, struct file *file)
 {
 	struct spufs_inode_info *i = SPUFS_I(inode);
+	struct spu_context *ctx = i->i_ctx;
 
 	file->private_data = i->i_ctx;
+	ctx->psmap = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
@@ -1114,6 +1120,8 @@ static int spufs_mfc_open(struct inode *
 		return -EBUSY;
 
 	file->private_data = ctx;
+	ctx->mfc = inode->i_mapping;
+	smp_wmb();
 	return nonseekable_open(inode, file);
 }
 
Index: linux-cell/arch/powerpc/platforms/cell/spufs/spufs.h
===================================================================
--- linux-cell.orig/arch/powerpc/platforms/cell/spufs/spufs.h	2007-02-09 15:47:28.000000000 +1100
+++ linux-cell/arch/powerpc/platforms/cell/spufs/spufs.h	2007-02-09 15:48:15.000000000 +1100
@@ -51,6 +51,8 @@ struct spu_context {
 	struct address_space *cntl; 	   /* 'control' area mappings. */
 	struct address_space *signal1; 	   /* 'signal1' area mappings. */
 	struct address_space *signal2; 	   /* 'signal2' area mappings. */
+	struct address_space *mss; 	   /* 'mss' area mappings. */
+	struct address_space *psmap; 	   /* 'psmap' area mappings. */
 	u64 object_id;		   /* user space pointer for oprofile */
 
 	enum { SPU_STATE_RUNNABLE, SPU_STATE_SAVED } state;

Re: [Cbe-oss-dev] [PATCH] spufs: Fix bitrot of the SPU mmap facility (#2)

[Christoph Hellwig]

On Fri, Feb 09, 2007 at 04:52:10PM +1100, Benjamin Herrenschmidt wrote:
> spufs: Fix bitrot of the SPU mmap facility
> 
> It looks like we've had some serious bitrot there mostly due to tracking
> of address_space's of mmap'ed files getting out of sync with the actual
> mmap code. The mfc, mss and psmap were not tracked properly and thus
> not invalidated on context switches (oops !)
> 
> I also removed the various file->f_mapping = inode->i_mapping;
> assignments that were done in the other open() routines since that
> is already done for us by __dentry_open.
> 
> One improvement we might want to do later is to assign the various
> ctx-> fields at mmap time instead of file open/close time so that we
> don't call unmap_mapping_range() on thing that have not been mmap'ed
> 
> Finally, I added some smp_wmb's after assigning the ctx-> fields to make
> sure they are visible to other CPUs. I don't think this is really
> necessary as I suspect locking in the fs layer will make that happen
> anyway but better safe than sorry.


Looks good to me.