scst_cmd_set_sn: remove lockless fast path#335
Merged
lnocturno merged 1 commit intoSCST-project:masterfrom Dec 11, 2025
Merged
Conversation
The lockless fast path for scst_cmd_set_sn() can cause commands to lockup in state EXEC_CHECK_SN when there are multiple scst_tgts accessing the same scst_device, for example two initiators connected to the two ports of a dual-port QLogic FC HBA in target mode both reading from the same shared disk. The multithreaded_init_done value is too low-level for this; it does not take the higher-level configuration into account. - Remove the lockless fast path. - Remove multithreaded_init_done, which enabled/disabled the lockless fast path. - Push the locking down into scst_cmd_set_sn(), which will now apply regardless of set_sn_on_restart_cmd, which matters for mixed-driver (e.g. iSCSI+qla2xxx) target-mode setups. - Remove a bunch of comments explaining the rules for the lockless fast path. Fixes: SCST-project#333 Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
abattersby
force-pushed
the
remove-lockless-fast-path
branch
from
4259c07 to
e35fddb
Compare
Contributor
Author
|
I tested with qla2x00t-32gbit but not any other target drivers. Recommend testing with at least iSCSI. |
Contributor
|
Hi Tony, Thank you for the patch! Thanks, |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
The lockless fast path for scst_cmd_set_sn() can cause commands to lockup in state EXEC_CHECK_SN when there are multiple scst_tgts accessing the same scst_device, for example two initiators connected to the two ports of a dual-port QLogic FC HBA in target mode both reading from the same shared disk. The multithreaded_init_done value is too low-level for this; it does not take the higher-level configuration into account.
Fixes: #333