This is a note to let you know that I've just added the patch titled
crypto: qat - remove unnecessary collision prevention step in PFVF
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
crypto-qat-remove-unnecessary-collision-prevention-s.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9a1d1326e3e5935c1c2c112c257f6aef1b461343
Author: Marco Chiappero <marco.chiappero@xxxxxxxxx>
Date: Tue Sep 28 12:44:31 2021 +0100
crypto: qat - remove unnecessary collision prevention step in PFVF
[ Upstream commit e17f49bb244a281fe39bfdad0306a38b3a02e7bf ]
The initial version of the PFVF protocol included an initial "carrier
sensing" to get ownership of the channel.
Collisions can happen anyway, the extra wait and test does not prevent
collisions, it instead slows the communication down, so remove it.
Signed-off-by: Marco Chiappero <marco.chiappero@xxxxxxxxx>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@xxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c b/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c
index e3da97286980e..d1dbf6216de57 100644
--- a/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c
+++ b/drivers/crypto/qat/qat_common/adf_pf2vf_msg.c
@@ -120,28 +120,10 @@ static int __adf_iov_putmsg(struct adf_accel_dev *accel_dev, u32 msg, u8 vf_nr)
goto out;
}
- /* Attempt to get ownership of PF2VF CSR */
msg &= ~local_in_use_mask;
msg |= local_in_use_pattern;
- ADF_CSR_WR(pmisc_bar_addr, pf2vf_offset, msg);
- /* Wait in case remote func also attempting to get ownership */
- msleep(ADF_IOV_MSG_COLLISION_DETECT_DELAY);
-
- val = ADF_CSR_RD(pmisc_bar_addr, pf2vf_offset);
- if ((val & local_in_use_mask) != local_in_use_pattern) {
- dev_dbg(&GET_DEV(accel_dev),
- "PF2VF CSR in use by remote - collision detected\n");
- ret = -EBUSY;
- goto out;
- }
-
- /*
- * This function now owns the PV2VF CSR. The IN_USE_BY pattern must
- * remain in the PF2VF CSR for all writes including ACK from remote
- * until this local function relinquishes the CSR. Send the message
- * by interrupting the remote.
- */
+ /* Attempt to get ownership of the PF2VF CSR */
ADF_CSR_WR(pmisc_bar_addr, pf2vf_offset, msg | int_bit);
/* Wait for confirmation from remote func it received the message */
