V Fri, 29 Mar 2024 12:28:09 -0700 Dexuan Cui decui@microsoft.com napsáno:
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") Cc: stable@vger.kernel.org Signed-off-by: Dexuan Cui decui@microsoft.com
FWIW I confirm that the transient_nslabs counter does not have to be initialized either.
Reviewed-by: Petr Tesarik petr.tesarik1@huawei-partners.com
Petr T