From: Tony Battersby <tonyb@cybernetics.com> To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: iommu@lists.linux-foundation.org, kernel-team@fb.com, Matthew Wilcox <willy@infradead.org>, Keith Busch <kbusch@kernel.org>, Andy Shevchenko <andy.shevchenko@gmail.com>, Robin Murphy <robin.murphy@arm.com>, Tony Lindgren <tony@atomide.com> Subject: [PATCH 06/10] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled Date: Tue, 31 May 2022 14:20:51 -0400 [thread overview] Message-ID: <d7499103-95c4-a002-cb6c-c8c5e3375a8d@cybernetics.com> (raw) In-Reply-To: <9b08ab7c-b80b-527d-9adf-7716b0868fbc@cybernetics.com> There are two cases: 1) In the normal case that the memory is being freed correctly, then DMAPOOL_DEBUG will memset the memory anyway, so speed things up by avoiding a double-memset of the same memory. 2) In the abnormal case that DMAPOOL_DEBUG detects that a driver passes incorrect parameters to dma_pool_free() (e.g. double-free, invalid free, mismatched vaddr/dma, etc.), then that is a kernel bug, and we don't want to clear the passed-in possibly-invalid memory pointer because we can't be sure that the memory is really free. So don't clear it just because init_on_free=1. Signed-off-by: Tony Battersby <tonyb@cybernetics.com> --- mm/dmapool.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 7a9161d4f7a6..49019ef6dd83 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -415,8 +415,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) } offset = vaddr - page->vaddr; - if (want_init_on_free()) - memset(vaddr, 0, pool->size); #ifdef DMAPOOL_DEBUG if ((dma - page->dma) != offset) { spin_unlock_irqrestore(&pool->lock, flags); @@ -461,6 +459,9 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) goto freelist_corrupt; } memset(vaddr, POOL_POISON_FREED, pool->size); +#else + if (want_init_on_free()) + memset(vaddr, 0, pool->size); #endif page->in_use--; -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Tony Battersby <tonyb@cybernetics.com> To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Tony Lindgren <tony@atomide.com>, Andy Shevchenko <andy.shevchenko@gmail.com>, Matthew Wilcox <willy@infradead.org>, iommu@lists.linux-foundation.org, Keith Busch <kbusch@kernel.org>, kernel-team@fb.com, Robin Murphy <robin.murphy@arm.com> Subject: [PATCH 06/10] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled Date: Tue, 31 May 2022 14:20:51 -0400 [thread overview] Message-ID: <d7499103-95c4-a002-cb6c-c8c5e3375a8d@cybernetics.com> (raw) In-Reply-To: <9b08ab7c-b80b-527d-9adf-7716b0868fbc@cybernetics.com> There are two cases: 1) In the normal case that the memory is being freed correctly, then DMAPOOL_DEBUG will memset the memory anyway, so speed things up by avoiding a double-memset of the same memory. 2) In the abnormal case that DMAPOOL_DEBUG detects that a driver passes incorrect parameters to dma_pool_free() (e.g. double-free, invalid free, mismatched vaddr/dma, etc.), then that is a kernel bug, and we don't want to clear the passed-in possibly-invalid memory pointer because we can't be sure that the memory is really free. So don't clear it just because init_on_free=1. Signed-off-by: Tony Battersby <tonyb@cybernetics.com> --- mm/dmapool.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 7a9161d4f7a6..49019ef6dd83 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -415,8 +415,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) } offset = vaddr - page->vaddr; - if (want_init_on_free()) - memset(vaddr, 0, pool->size); #ifdef DMAPOOL_DEBUG if ((dma - page->dma) != offset) { spin_unlock_irqrestore(&pool->lock, flags); @@ -461,6 +459,9 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) goto freelist_corrupt; } memset(vaddr, POOL_POISON_FREED, pool->size); +#else + if (want_init_on_free()) + memset(vaddr, 0, pool->size); #endif page->in_use--; -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2022-05-31 18:21 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-05-31 18:11 [PATCH 00/10] mpt3sas and dmapool scalability Tony Battersby 2022-05-31 18:11 ` Tony Battersby 2022-05-31 18:12 ` [PATCH 01/10] dmapool: remove checks for dev == NULL Tony Battersby 2022-05-31 18:12 ` Tony Battersby 2022-05-31 18:23 ` Robin Murphy 2022-05-31 18:23 ` Robin Murphy 2022-05-31 18:13 ` [PATCH 02/10] dmapool: cleanup integer types Tony Battersby 2022-05-31 18:13 ` Tony Battersby 2022-05-31 18:14 ` [PATCH 03/10] dmapool: fix boundary comparison Tony Battersby 2022-05-31 18:14 ` Tony Battersby 2022-05-31 18:17 ` [PATCH 04/10] dmapool: improve accuracy of debug statistics Tony Battersby 2022-05-31 18:17 ` Tony Battersby 2022-05-31 19:48 ` Robin Murphy 2022-05-31 19:48 ` Robin Murphy 2022-05-31 19:52 ` Tony Battersby 2022-05-31 19:52 ` Tony Battersby 2022-05-31 21:55 ` Robin Murphy 2022-05-31 21:55 ` Robin Murphy 2022-05-31 18:18 ` [PATCH 05/10] dmapool: debug: prevent endless loop in case of corruption Tony Battersby 2022-05-31 18:18 ` Tony Battersby 2022-05-31 18:20 ` Tony Battersby [this message] 2022-05-31 18:20 ` [PATCH 06/10] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled Tony Battersby 2022-05-31 18:21 ` [PATCH 07/10] dmapool: speedup DMAPOOL_DEBUG with init_on_alloc Tony Battersby 2022-05-31 18:21 ` Tony Battersby 2022-05-31 18:22 ` [PATCH 08/10] dmapool: cleanup dma_pool_destroy Tony Battersby 2022-05-31 18:22 ` Tony Battersby 2022-05-31 19:33 ` Robin Murphy 2022-05-31 19:33 ` Robin Murphy 2022-05-31 21:40 ` Keith Busch 2022-05-31 21:40 ` Keith Busch 2022-05-31 18:23 ` [PATCH 09/10] dmapool: improve scalability of dma_pool_alloc Tony Battersby 2022-05-31 18:23 ` Tony Battersby 2022-05-31 18:23 ` [PATCH 10/10] dmapool: improve scalability of dma_pool_free Tony Battersby 2022-05-31 18:23 ` Tony Battersby 2022-05-31 21:54 ` Keith Busch 2022-05-31 21:54 ` Keith Busch 2022-05-31 22:10 ` Tony Battersby 2022-05-31 22:10 ` Tony Battersby 2022-06-01 9:44 ` Robin Murphy 2022-06-01 9:44 ` Robin Murphy
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