This patch fixes an issue that the following error happens on
swiotlb environment:
xhci-hcd ee000000.usb: swiotlb buffer is full (sz: 524288 bytes), total 32768 (slots), used 1338 (slots)
On the kernel v5.1, block settings of a usb-storage with SuperSpeed
were the following so that the block layer will allocate buffers
up to 64 KiB, and then the issue didn't happen.
max_segment_size = 65536
max_hw_sectors_kb = 1024
After the commit 09324d32d2 ("block: force an unlimited segment
size on queues with a virt boundary") is applied, the block settings
are the following. So, the block layer will allocate buffers up to
1024 KiB, and then the issue happens:
max_segment_size = 4294967295
max_hw_sectors_kb = 1024
To fix the issue, the usb-storage driver checks the maximum size of
a mapping for the device and then adjusts the max_hw_sectors_kb
if required. After this patch is applied, the block settings will
be the following, and then the issue doesn't happen.
max_segment_size = 4294967295
max_hw_sectors_kb = 256
Fixes: 09324d32d2 ("block: force an unlimited segment size on queues with a virt boundary")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/1563793105-20597-1-git-send-email-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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