From: Leonardo Bras <leobras.c@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Leonardo Bras <leobras.c@gmail.com>,
Joel Stanley <joel@jms.id.au>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>,
Ram Pai <linuxram@us.ibm.com>,
Brian King <brking@linux.vnet.ibm.com>,
Murilo Fossa Vicentini <muvic@linux.ibm.com>,
David Dai <zdai@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v1 04/10] powerpc/kernel/iommu: Add new iommu_table_in_use() helper
Date: Mon, 17 Aug 2020 20:40:27 -0300 [thread overview]
Message-ID: <20200817234033.442511-5-leobras.c@gmail.com> (raw)
In-Reply-To: <20200817234033.442511-1-leobras.c@gmail.com>
Having a function to check if the iommu table has any allocation helps
deciding if a tbl can be reset for using a new DMA window.
It should be enough to replace all instances of !bitmap_empty(tbl...).
iommu_table_in_use() skips reserved memory, so we don't need to worry about
releasing it before testing. This causes iommu_table_release_pages() to
become unnecessary, given it is only used to remove reserved memory for
testing.
Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
---
arch/powerpc/include/asm/iommu.h | 1 +
arch/powerpc/kernel/iommu.c | 62 ++++++++++++++++++--------------
2 files changed, 37 insertions(+), 26 deletions(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 5032f1593299..2913e5c8b1f8 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -154,6 +154,7 @@ extern int iommu_tce_table_put(struct iommu_table *tbl);
*/
extern struct iommu_table *iommu_init_table(struct iommu_table *tbl,
int nid, unsigned long res_start, unsigned long res_end);
+bool iommu_table_in_use(struct iommu_table *tbl);
#define IOMMU_TABLE_GROUP_MAX_TABLES 2
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 7f603d4e62d4..c5d5d36ab65e 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -668,21 +668,6 @@ static void iommu_table_reserve_pages(struct iommu_table *tbl,
set_bit(i - tbl->it_offset, tbl->it_map);
}
-static void iommu_table_release_pages(struct iommu_table *tbl)
-{
- int i;
-
- /*
- * In case we have reserved the first bit, we should not emit
- * the warning below.
- */
- if (tbl->it_offset == 0)
- clear_bit(0, tbl->it_map);
-
- for (i = tbl->it_reserved_start; i < tbl->it_reserved_end; ++i)
- clear_bit(i - tbl->it_offset, tbl->it_map);
-}
-
/*
* Build a iommu_table structure. This contains a bit map which
* is used to manage allocation of the tce space.
@@ -743,6 +728,38 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid,
return tbl;
}
+bool iommu_table_in_use(struct iommu_table *tbl)
+{
+ bool in_use;
+ unsigned long p1_start = 0, p1_end, p2_start, p2_end;
+
+ /*ignore reserved bit0*/
+ if (tbl->it_offset == 0)
+ p1_start = 1;
+
+ /* Check if reserved memory is valid*/
+ if (tbl->it_reserved_start >= tbl->it_offset &&
+ tbl->it_reserved_start <= (tbl->it_offset + tbl->it_size) &&
+ tbl->it_reserved_end >= tbl->it_offset &&
+ tbl->it_reserved_end <= (tbl->it_offset + tbl->it_size)) {
+ p1_end = tbl->it_reserved_start - tbl->it_offset;
+ p2_start = tbl->it_reserved_end - tbl->it_offset + 1;
+ p2_end = tbl->it_size;
+ } else {
+ p1_end = tbl->it_size;
+ p2_start = 0;
+ p2_end = 0;
+ }
+
+ in_use = (find_next_bit(tbl->it_map, p1_end, p1_start) != p1_end);
+ if (in_use || p2_start == 0)
+ return in_use;
+
+ in_use = (find_next_bit(tbl->it_map, p2_end, p2_start) != p2_end);
+
+ return in_use;
+}
+
static void iommu_table_free(struct kref *kref)
{
unsigned long bitmap_sz;
@@ -759,10 +776,8 @@ static void iommu_table_free(struct kref *kref)
return;
}
- iommu_table_release_pages(tbl);
-
/* verify that table contains no entries */
- if (!bitmap_empty(tbl->it_map, tbl->it_size))
+ if (iommu_table_in_use(tbl))
pr_warn("%s: Unexpected TCEs\n", __func__);
/* calculate bitmap size in bytes */
@@ -1069,18 +1084,13 @@ int iommu_take_ownership(struct iommu_table *tbl)
for (i = 0; i < tbl->nr_pools; i++)
spin_lock(&tbl->pools[i].lock);
- iommu_table_release_pages(tbl);
-
- if (!bitmap_empty(tbl->it_map, tbl->it_size)) {
+ if (iommu_table_in_use(tbl)) {
pr_err("iommu_tce: it_map is not empty");
ret = -EBUSY;
- /* Undo iommu_table_release_pages, i.e. restore bit#0, etc */
- iommu_table_reserve_pages(tbl, tbl->it_reserved_start,
- tbl->it_reserved_end);
- } else {
- memset(tbl->it_map, 0xff, sz);
}
+ memset(tbl->it_map, 0xff, sz);
+
for (i = 0; i < tbl->nr_pools; i++)
spin_unlock(&tbl->pools[i].lock);
spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
--
2.25.4
next prev parent reply other threads:[~2020-08-17 23:53 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-17 23:40 [PATCH v1 00/10] DDW indirect mapping Leonardo Bras
2020-08-17 23:40 ` [PATCH v1 01/10] powerpc/pseries/iommu: Replace hard-coded page shift Leonardo Bras
2020-08-22 9:33 ` Alexey Kardashevskiy
2020-08-27 15:32 ` Leonardo Bras
2020-08-28 2:27 ` Alexey Kardashevskiy
2020-08-28 19:55 ` Leonardo Bras
2020-08-31 0:06 ` Alexey Kardashevskiy
2020-08-31 1:41 ` Oliver O'Halloran
2020-08-31 3:48 ` Alexey Kardashevskiy
2020-09-01 21:38 ` Leonardo Bras
2020-09-03 4:26 ` Alexey Kardashevskiy
2020-08-17 23:40 ` [PATCH v1 02/10] powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE on iommu_*_coherent() Leonardo Bras
2020-08-22 10:07 ` Alexey Kardashevskiy
2020-08-27 16:51 ` Leonardo Bras
2020-08-28 1:40 ` Alexey Kardashevskiy
2020-08-28 20:41 ` Leonardo Bras
2020-08-31 0:47 ` Alexey Kardashevskiy
2020-09-01 22:34 ` Leonardo Bras
2020-09-03 4:41 ` Alexey Kardashevskiy
2020-09-04 6:04 ` Leonardo Bras
2020-09-08 3:18 ` Alexey Kardashevskiy
2020-08-17 23:40 ` [PATCH v1 03/10] powerpc/kernel/iommu: Use largepool as a last resort when !largealloc Leonardo Bras
2020-08-22 10:09 ` Alexey Kardashevskiy
2020-08-27 16:58 ` Leonardo Bras
2020-08-17 23:40 ` Leonardo Bras [this message]
2020-08-22 10:34 ` [PATCH v1 04/10] powerpc/kernel/iommu: Add new iommu_table_in_use() helper Alexey Kardashevskiy
2020-08-27 18:34 ` Leonardo Bras
2020-08-28 1:51 ` Alexey Kardashevskiy
2020-08-17 23:40 ` [PATCH v1 05/10] powerpc/pseries/iommu: Add iommu_pseries_alloc_table() helper Leonardo Bras
2020-08-24 0:38 ` Alexey Kardashevskiy
2020-08-27 21:23 ` Leonardo Bras
2020-08-17 23:40 ` [PATCH v1 06/10] powerpc/pseries/iommu: Add ddw_list_add() helper Leonardo Bras
2020-08-24 3:46 ` Alexey Kardashevskiy
2020-08-27 22:11 ` Leonardo Bras
2020-08-28 1:58 ` Alexey Kardashevskiy
2020-08-28 21:28 ` Leonardo Bras
2020-08-17 23:40 ` [PATCH v1 07/10] powerpc/pseries/iommu: Allow DDW windows starting at 0x00 Leonardo Bras
2020-08-24 3:44 ` Alexey Kardashevskiy
2020-08-28 14:04 ` Leonardo Bras
2020-08-31 0:50 ` Alexey Kardashevskiy
2020-08-17 23:40 ` [PATCH v1 08/10] powerpc/pseries/iommu: Add ddw_property_create() and refactor enable_ddw() Leonardo Bras
2020-08-24 5:07 ` Alexey Kardashevskiy
2020-08-28 15:25 ` Leonardo Bras
2020-08-31 4:34 ` Alexey Kardashevskiy
2020-09-02 5:27 ` Leonardo Bras
2020-08-17 23:40 ` [PATCH v1 09/10] powerpc/pseries/iommu: Make use of DDW even if it does not map the partition Leonardo Bras
2020-08-24 5:17 ` Alexey Kardashevskiy
2020-08-28 18:36 ` Leonardo Bras
2020-08-31 4:35 ` Alexey Kardashevskiy
2020-09-02 6:11 ` Leonardo Bras
2020-09-04 1:00 ` Alexey Kardashevskiy
2020-08-17 23:40 ` [PATCH v1 10/10] powerpc/pseries/iommu: Rename "direct window" to "dma window" Leonardo Bras
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