All of lore.kernel.org
 help / color / mirror / Atom feed
From: Vasily Averin <vvs@openvz.org>
To: Dan Williams <dan.j.williams@intel.com>,
	Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Cc: kernel@openvz.org, linux-kernel@vger.kernel.org,
	nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org
Subject: [PATCH v2] sparse: use force attribute for vm_fault_t casts
Date: Sat, 14 May 2022 22:56:04 +0300	[thread overview]
Message-ID: <66e8e17a-73c2-2e50-cdc2-ed924d6bfb2a@openvz.org> (raw)
In-Reply-To: <Yn/oKz6v5GkReeA3@casper.infradead.org>

Fixes sparse warnings:
./include/trace/events/fs_dax.h:10:1: sparse:
    got restricted vm_fault_t
./include/trace/events/fs_dax.h:153:1: sparse:
    got restricted vm_fault_t
fs/dax.c:563:39: sparse:    got restricted vm_fault_t
fs/dax.c:565:39: sparse:    got restricted vm_fault_t
fs/dax.c:569:31: sparse:    got restricted vm_fault_t
fs/dax.c:1055:41: sparse:
    got restricted vm_fault_t [assigned] [usertype] ret
fs/dax.c:1461:46: sparse:    got restricted vm_fault_t [usertype] ret
fs/dax.c:1477:21: sparse:
    expected restricted vm_fault_t [assigned] [usertype] ret
fs/dax.c:1518:51: sparse:
    got restricted vm_fault_t [assigned] [usertype] ret
fs/dax.c:1599:21: sparse:
    expected restricted vm_fault_t [assigned] [usertype] ret
fs/dax.c:1633:62: sparse:
    got restricted vm_fault_t [assigned] [usertype] ret
fs/dax.c:1696:55: sparse:    got restricted vm_fault_t
fs/dax.c:1711:58: sparse:
    got restricted vm_fault_t [assigned] [usertype] ret

vm_fault_t type is bitwise and requires __force attribute for any casts.

Signed-off-by: Vasily Averin <vvs@openvz.org>
---
v2: improved according to the recommendations of Matthew Wilcox:
   - __force cast moved into internal functions
   - introduced new abstractions dax_vm_fault_[en|de]code()
---
 fs/dax.c                      | 21 +++++++++++++++------
 include/linux/mm_types.h      | 30 ++++++++++++++++--------------
 include/trace/events/fs_dax.h | 12 ++++++------
 3 files changed, 37 insertions(+), 26 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 67a08a32fccb..c27c8782007f 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -121,6 +121,15 @@ static int dax_is_empty_entry(void *entry)
 	return xa_to_value(entry) & DAX_EMPTY;
 }
 
+static void *dax_vm_fault_encode(vm_fault_t fault)
+{
+	return xa_mk_internal((__force unsigned long)fault);
+}
+
+static vm_fault_t dax_vm_fault_decode(void *entry)
+{
+	return (__force vm_fault_t)xa_to_internal(entry);
+}
 /*
  * true if the entry that was found is of a smaller order than the entry
  * we were looking for
@@ -560,13 +569,13 @@ static void *grab_mapping_entry(struct xa_state *xas,
 	if (xas_nomem(xas, mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM))
 		goto retry;
 	if (xas->xa_node == XA_ERROR(-ENOMEM))
-		return xa_mk_internal(VM_FAULT_OOM);
+		return dax_vm_fault_encode(VM_FAULT_OOM);
 	if (xas_error(xas))
-		return xa_mk_internal(VM_FAULT_SIGBUS);
+		return dax_vm_fault_encode(VM_FAULT_SIGBUS);
 	return entry;
 fallback:
 	xas_unlock_irq(xas);
-	return xa_mk_internal(VM_FAULT_FALLBACK);
+	return dax_vm_fault_encode(VM_FAULT_FALLBACK);
 }
 
 /**
@@ -1474,7 +1483,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
 
 	entry = grab_mapping_entry(&xas, mapping, 0);
 	if (xa_is_internal(entry)) {
-		ret = xa_to_internal(entry);
+		ret = dax_vm_fault_decode(entry);
 		goto out;
 	}
 
@@ -1578,7 +1587,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	 */
 	max_pgoff = DIV_ROUND_UP(i_size_read(iter.inode), PAGE_SIZE);
 
-	trace_dax_pmd_fault(iter.inode, vmf, max_pgoff, 0);
+	trace_dax_pmd_fault(iter.inode, vmf, max_pgoff, (vm_fault_t)0);
 
 	if (xas.xa_index >= max_pgoff) {
 		ret = VM_FAULT_SIGBUS;
@@ -1596,7 +1605,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	 */
 	entry = grab_mapping_entry(&xas, mapping, PMD_ORDER);
 	if (xa_is_internal(entry)) {
-		ret = xa_to_internal(entry);
+		ret = dax_vm_fault_decode(entry);
 		goto fallback;
 	}
 
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8834e38c06a4..57cc4918b1b1 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -745,20 +745,22 @@ enum vm_fault_reason {
 			VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON |	\
 			VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK)
 
-#define VM_FAULT_RESULT_TRACE \
-	{ VM_FAULT_OOM,                 "OOM" },	\
-	{ VM_FAULT_SIGBUS,              "SIGBUS" },	\
-	{ VM_FAULT_MAJOR,               "MAJOR" },	\
-	{ VM_FAULT_WRITE,               "WRITE" },	\
-	{ VM_FAULT_HWPOISON,            "HWPOISON" },	\
-	{ VM_FAULT_HWPOISON_LARGE,      "HWPOISON_LARGE" },	\
-	{ VM_FAULT_SIGSEGV,             "SIGSEGV" },	\
-	{ VM_FAULT_NOPAGE,              "NOPAGE" },	\
-	{ VM_FAULT_LOCKED,              "LOCKED" },	\
-	{ VM_FAULT_RETRY,               "RETRY" },	\
-	{ VM_FAULT_FALLBACK,            "FALLBACK" },	\
-	{ VM_FAULT_DONE_COW,            "DONE_COW" },	\
-	{ VM_FAULT_NEEDDSYNC,           "NEEDDSYNC" }
+#define faultflag_string(flag) {(__force unsigned long)VM_FAULT_##flag, #flag}
+
+#define VM_FAULT_RESULT_TRACE			\
+	faultflag_string(OOM),			\
+	faultflag_string(SIGBUS),		\
+	faultflag_string(MAJOR),		\
+	faultflag_string(WRITE),		\
+	faultflag_string(HWPOISON),		\
+	faultflag_string(HWPOISON_LARGE),	\
+	faultflag_string(SIGSEGV),		\
+	faultflag_string(NOPAGE),		\
+	faultflag_string(LOCKED),		\
+	faultflag_string(RETRY),		\
+	faultflag_string(FALLBACK),		\
+	faultflag_string(DONE_COW),		\
+	faultflag_string(NEEDDSYNC)
 
 struct vm_special_mapping {
 	const char *name;	/* The name, e.g. "[vdso]". */
diff --git a/include/trace/events/fs_dax.h b/include/trace/events/fs_dax.h
index 97b09fcf7e52..75908bdc7b2d 100644
--- a/include/trace/events/fs_dax.h
+++ b/include/trace/events/fs_dax.h
@@ -9,7 +9,7 @@
 
 DECLARE_EVENT_CLASS(dax_pmd_fault_class,
 	TP_PROTO(struct inode *inode, struct vm_fault *vmf,
-		pgoff_t max_pgoff, int result),
+		pgoff_t max_pgoff, vm_fault_t result),
 	TP_ARGS(inode, vmf, max_pgoff, result),
 	TP_STRUCT__entry(
 		__field(unsigned long, ino)
@@ -33,7 +33,7 @@ DECLARE_EVENT_CLASS(dax_pmd_fault_class,
 		__entry->flags = vmf->flags;
 		__entry->pgoff = vmf->pgoff;
 		__entry->max_pgoff = max_pgoff;
-		__entry->result = result;
+		__entry->result = (__force int)result;
 	),
 	TP_printk("dev %d:%d ino %#lx %s %s address %#lx vm_start "
 			"%#lx vm_end %#lx pgoff %#lx max_pgoff %#lx %s",
@@ -54,7 +54,7 @@ DECLARE_EVENT_CLASS(dax_pmd_fault_class,
 #define DEFINE_PMD_FAULT_EVENT(name) \
 DEFINE_EVENT(dax_pmd_fault_class, name, \
 	TP_PROTO(struct inode *inode, struct vm_fault *vmf, \
-		pgoff_t max_pgoff, int result), \
+		pgoff_t max_pgoff, vm_fault_t result), \
 	TP_ARGS(inode, vmf, max_pgoff, result))
 
 DEFINE_PMD_FAULT_EVENT(dax_pmd_fault);
@@ -151,7 +151,7 @@ DEFINE_EVENT(dax_pmd_insert_mapping_class, name, \
 DEFINE_PMD_INSERT_MAPPING_EVENT(dax_pmd_insert_mapping);
 
 DECLARE_EVENT_CLASS(dax_pte_fault_class,
-	TP_PROTO(struct inode *inode, struct vm_fault *vmf, int result),
+	TP_PROTO(struct inode *inode, struct vm_fault *vmf, vm_fault_t result),
 	TP_ARGS(inode, vmf, result),
 	TP_STRUCT__entry(
 		__field(unsigned long, ino)
@@ -169,7 +169,7 @@ DECLARE_EVENT_CLASS(dax_pte_fault_class,
 		__entry->address = vmf->address;
 		__entry->flags = vmf->flags;
 		__entry->pgoff = vmf->pgoff;
-		__entry->result = result;
+		__entry->result = (__force int)result;
 	),
 	TP_printk("dev %d:%d ino %#lx %s %s address %#lx pgoff %#lx %s",
 		MAJOR(__entry->dev),
@@ -185,7 +185,7 @@ DECLARE_EVENT_CLASS(dax_pte_fault_class,
 
 #define DEFINE_PTE_FAULT_EVENT(name) \
 DEFINE_EVENT(dax_pte_fault_class, name, \
-	TP_PROTO(struct inode *inode, struct vm_fault *vmf, int result), \
+	TP_PROTO(struct inode *inode, struct vm_fault *vmf, vm_fault_t result), \
 	TP_ARGS(inode, vmf, result))
 
 DEFINE_PTE_FAULT_EVENT(dax_pte_fault);
-- 
2.31.1


      reply	other threads:[~2022-05-14 19:56 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-14 14:26 [PATCH] sparse: use force attribute for vm_fault_t casts Vasily Averin
2022-05-14 17:34 ` Matthew Wilcox
2022-05-14 19:56   ` Vasily Averin [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=66e8e17a-73c2-2e50-cdc2-ed924d6bfb2a@openvz.org \
    --to=vvs@openvz.org \
    --cc=dan.j.williams@intel.com \
    --cc=jack@suse.cz \
    --cc=kernel@openvz.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=nvdimm@lists.linux.dev \
    --cc=viro@zeniv.linux.org.uk \
    --cc=willy@infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.