scsi: ufs: core: Avoid possible memory reclaim deadlock in TX EQTR context

Browse source

TX EQTR may run while devfreq gear scaling has quiesced the UFS
tagset. In that context, functions ufshcd_tx_eqtr(), __ufshcd_tx_eqtr()
and ufs_qcom_get_rx_fom() allocate memory with GFP_KERNEL. If direct
reclaim is triggered, reclaim/writeback can depend on I/O to UFS
device. Because the queue is quiesced, this can cause deadlock.

Use memalloc_noio_save/restore() in ufshcd_tx_eqtr() to cover all
allocations in the TX EQTR call tree, including:

 - params->eqtr_record in ufshcd_tx_eqtr()

 - eqtr_data in __ufshcd_tx_eqtr()

 - params in ufs_qcom_get_rx_fom()

This is preferred over tagging individual call sites with GFP_NOIO, as it
automatically covers any future allocations added anywhere in the call tree
without requiring each caller to be aware of this constraint.

[mkp: fix label as suggested by Bart]

Fixes: 03e5d38e2f ("scsi: ufs: core: Add support for TX Equalization")
Closes: https://sashiko.dev/#/patchset/20260615132834.2985346-1-can.guo@oss.qualcomm.com?part=2
Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
Reviewed-by: Ziqi Chen <ziqi.chen@oss.qualcomm.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20260618140941.902000-1-can.guo@oss.qualcomm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

...

This commit is contained in:

Can Guo 2026-06-18 07:09:29 -07:00 • committed by Martin K. Petersen

parent e700a7c94f

commit 760fc6f0e2

1 changed files with 21 additions and 6 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

27

drivers/ufs/core/ufs-txeq.c

View file