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authorDexuan Cui <decui@microsoft.com>2024-03-29 12:28:09 -0700
committerChristoph Hellwig <hch@lst.de>2024-04-02 17:08:09 +0200
commita1255ccab8ecee89905ddb12161139b0d878a7f2 (patch)
tree96303c8896872d3b3bb600b3774f7bcfba78f3e6 /kernel/dma
parente8068f2d756d57a5206fa3180ade365a8c12ed85 (diff)
swiotlb: do not set total_used to 0 in swiotlb_create_debugfs_files()
Sometimes the readout of /sys/kernel/debug/swiotlb/io_tlb_used and io_tlb_used_hiwater can be a huge number (e.g. 18446744073709551615), which is actually a negative number if we use "%ld" to print the number. When swiotlb_create_default_debugfs() is running from late_initcall, mem->total_used may already be non-zero, because the storage driver may have already started to perform I/O operations: if the storage driver is built-in, its probe() callback is called before late_initcall. swiotlb_create_debugfs_files() should not blindly set mem->total_used and mem->used_hiwater to 0; actually it doesn't have to initialize the fields at all, because the fields, as part of the global struct io_tlb_default_mem, have been implicitly initialized to zero. Also don't explicitly set mem->transient_nslabs to 0. Fixes: 8b0977ecc8b3 ("swiotlb: track and report io_tlb_used high water marks in debugfs") Fixes: 02e765697038 ("swiotlb: add debugfs to track swiotlb transient pool usage") Signed-off-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: ZhangPeng <zhangpeng362@huawei.com> Reviewed-by: Petr Tesarik <petr.tesarik1@huawei-partners.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma')
-rw-r--r--kernel/dma/swiotlb.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index d57c8837c813..a5e0dfc44d24 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -1676,9 +1676,6 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_io_tlb_hiwater, io_tlb_hiwater_get,
static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem,
const char *dirname)
{
- atomic_long_set(&mem->total_used, 0);
- atomic_long_set(&mem->used_hiwater, 0);
-
mem->debugfs = debugfs_create_dir(dirname, io_tlb_default_mem.debugfs);
if (!mem->nslabs)
return;
@@ -1689,7 +1686,6 @@ static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem,
debugfs_create_file("io_tlb_used_hiwater", 0600, mem->debugfs, mem,
&fops_io_tlb_hiwater);
#ifdef CONFIG_SWIOTLB_DYNAMIC
- atomic_long_set(&mem->transient_nslabs, 0);
debugfs_create_file("io_tlb_transient_nslabs", 0400, mem->debugfs,
mem, &fops_io_tlb_transient_used);
#endif