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

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: 03e5d38e2f98 ("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>

0 files changed, 0 insertions, 0 deletions