From 796e4390e0378e1e57c033349610cfc741696a3d Mon Sep 17 00:00:00 2001 From: Muli Ben-Yehuda Date: Tue, 26 Sep 2006 10:52:33 +0200 Subject: [PATCH] [PATCH] only verify the allocation bitmap if CONFIG_IOMMU_DEBUG is on Introduce new function verify_bit_range(). Define two versions, one for CONFIG_IOMMU_DEBUG enabled and one for disabled. Previously we were checking that the bitmap was consistent every time we allocated or freed an entry in the TCE table, which is good for debugging but incurs an unnecessary penalty on non debug builds. Signed-off-by: Muli Ben-Yehuda Signed-off-by: Jon Mason Signed-off-by: Andi Kleen --- arch/x86_64/kernel/pci-calgary.c | 44 +++++++++++++++++++++++++------- 1 file changed, 35 insertions(+), 9 deletions(-) diff --git a/arch/x86_64/kernel/pci-calgary.c b/arch/x86_64/kernel/pci-calgary.c index ebe4e930b64d..7c43cb0f71a3 100644 --- a/arch/x86_64/kernel/pci-calgary.c +++ b/arch/x86_64/kernel/pci-calgary.c @@ -133,12 +133,35 @@ static inline void tce_cache_blast_stress(struct iommu_table *tbl) { tce_cache_blast(tbl); } + +static inline unsigned long verify_bit_range(unsigned long* bitmap, + int expected, unsigned long start, unsigned long end) +{ + unsigned long idx = start; + + BUG_ON(start >= end); + + while (idx < end) { + if (!!test_bit(idx, bitmap) != expected) + return idx; + ++idx; + } + + /* all bits have the expected value */ + return ~0UL; +} #else /* debugging is disabled */ int debugging __read_mostly = 0; static inline void tce_cache_blast_stress(struct iommu_table *tbl) { } + +static inline unsigned long verify_bit_range(unsigned long* bitmap, + int expected, unsigned long start, unsigned long end) +{ + return ~0UL; +} #endif /* CONFIG_IOMMU_DEBUG */ static inline unsigned int num_dma_pages(unsigned long dma, unsigned int dmalen) @@ -162,6 +185,7 @@ static void iommu_range_reserve(struct iommu_table *tbl, { unsigned long index; unsigned long end; + unsigned long badbit; index = start_addr >> PAGE_SHIFT; @@ -173,14 +197,15 @@ static void iommu_range_reserve(struct iommu_table *tbl, if (end > tbl->it_size) /* don't go off the table */ end = tbl->it_size; - while (index < end) { - if (test_bit(index, tbl->it_map)) + badbit = verify_bit_range(tbl->it_map, 0, index, end); + if (badbit != ~0UL) { + if (printk_ratelimit()) printk(KERN_ERR "Calgary: entry already allocated at " "0x%lx tbl %p dma 0x%lx npages %u\n", - index, tbl, start_addr, npages); - ++index; + badbit, tbl, start_addr, npages); } - set_bit_string(tbl->it_map, start_addr >> PAGE_SHIFT, npages); + + set_bit_string(tbl->it_map, index, npages); } static unsigned long iommu_range_alloc(struct iommu_table *tbl, @@ -247,7 +272,7 @@ static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr, unsigned int npages) { unsigned long entry; - unsigned long i; + unsigned long badbit; entry = dma_addr >> PAGE_SHIFT; @@ -255,11 +280,12 @@ static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr, tce_free(tbl, entry, npages); - for (i = 0; i < npages; ++i) { - if (!test_bit(entry + i, tbl->it_map)) + badbit = verify_bit_range(tbl->it_map, 1, entry, entry + npages); + if (badbit != ~0UL) { + if (printk_ratelimit()) printk(KERN_ERR "Calgary: bit is off at 0x%lx " "tbl %p dma 0x%Lx entry 0x%lx npages %u\n", - entry + i, tbl, dma_addr, entry, npages); + badbit, tbl, dma_addr, entry, npages); } __clear_bit_string(tbl->it_map, entry, npages); -- 2.39.5