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| author | Alan Stern <stern@rowland.harvard.edu> | 2019-10-21 11:48:06 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-28 17:52:44 +0100 |
| commit | 9a976949613132977098fc49510b46fa8678d864 (patch) | |
| tree | 4dbb0bbb39d9e13da63ba63bb158b1b8de46c867 | |
| parent | d4d8257754c3300ea2a465dadf8d2b02c713c920 (diff) | |
| download | linux-9a976949613132977098fc49510b46fa8678d864.tar.gz linux-9a976949613132977098fc49510b46fa8678d864.tar.bz2 linux-9a976949613132977098fc49510b46fa8678d864.zip | |
usb-storage: Revert commit 747668dbc061 ("usb-storage: Set virt_boundary_mask to avoid SG overflows")
Commit 747668dbc061 ("usb-storage: Set virt_boundary_mask to avoid SG
overflows") attempted to solve a problem involving scatter-gather I/O
and USB/IP by setting the virt_boundary_mask for mass-storage devices.
However, it now turns out that this interacts badly with commit
09324d32d2a0 ("block: force an unlimited segment size on queues with a
virt boundary"), which was added later. A typical error message is:
ehci-pci 0000:00:13.2: swiotlb buffer is full (sz: 327680 bytes),
total 32768 (slots), used 97 (slots)
There is no longer any reason to keep the virt_boundary_mask setting
for usb-storage. It was needed in the first place only for handling
devices with a block size smaller than the maxpacket size and where
the host controller was not capable of fully general scatter-gather
operation (that is, able to merge two SG segments into a single USB
packet). But:
High-speed or slower connections never use a bulk maxpacket
value larger than 512;
The SCSI layer does not handle block devices with a block size
smaller than 512 bytes;
All the host controllers capable of SuperSpeed operation can
handle fully general SG;
Since commit ea44d190764b ("usbip: Implement SG support to
vhci-hcd and stub driver") was merged, the USB/IP driver can
also handle SG.
Therefore all supported device/controller combinations should be okay
with no need for any special virt_boundary_mask. So in order to fix
the swiotlb problem, this patch reverts commit 747668dbc061.
Reported-and-tested-by: Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>
Link: https://marc.info/?l=linux-usb&m=157134199501202&w=2
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Seth Bollinger <Seth.Bollinger@digi.com>
CC: <stable@vger.kernel.org>
Fixes: 747668dbc061 ("usb-storage: Set virt_boundary_mask to avoid SG overflows")
Acked-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.1910211145520.1673-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/storage/scsiglue.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c index 6737fab94959..54a3c8195c96 100644 --- a/drivers/usb/storage/scsiglue.c +++ b/drivers/usb/storage/scsiglue.c @@ -68,7 +68,6 @@ static const char* host_info(struct Scsi_Host *host) static int slave_alloc (struct scsi_device *sdev) { struct us_data *us = host_to_us(sdev->host); - int maxp; /* * Set the INQUIRY transfer length to 36. We don't use any of @@ -78,15 +77,6 @@ static int slave_alloc (struct scsi_device *sdev) sdev->inquiry_len = 36; /* - * USB has unusual scatter-gather requirements: the length of each - * scatterlist element except the last must be divisible by the - * Bulk maxpacket value. Fortunately this value is always a - * power of 2. Inform the block layer about this requirement. - */ - maxp = usb_maxpacket(us->pusb_dev, us->recv_bulk_pipe, 0); - blk_queue_virt_boundary(sdev->request_queue, maxp - 1); - - /* * Some host controllers may have alignment requirements. * We'll play it safe by requiring 512-byte alignment always. */ |