Module Name: src
Committed By: riastradh
Date: Fri Apr 21 18:25:49 UTC 2023
Modified Files:
src/sys/dev/dkwedge: dk.c
Log Message:
dk(4): Prevent races in access to struct dkwedge_softc::sc_size.
Rules:
1. Only ever increases, never decreases.
(Decreases require removing and readding the wedge.)
2. Increases are serialized by dk_openlock.
3. Reads can happen unlocked in any context where the softc is valid.
Access is gathered into dkwedge_size* subroutines -- don't touch
sc_size outside these. For now, we use rwlock(9) to keep the
reasoning simple. This should be done with atomics on 64-bit
platforms and a seqlock on 32-bit platforms to avoid contention.
However, we can do that in a later change.
To generate a diff of this commit:
cvs rdiff -u -r1.134 -r1.135 src/sys/dev/dkwedge/dk.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
