6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Previn [ Upstream commit e7ed652b1312ffcb9ea2153946615856b5097c78 ] Check for overflow in udelay use in __xe_mmio_wait32 and avoid growing delays becoming intollerably large by capping the in-loop wait time. v7: - Change assisted-by to "LLM" (Rodrigo). - Move the max-wait macro to outside the function (Rodrigo). v6: - Fix commit message to remove items dropped in v5. Fix the use of MAX_UDELAY_MS for microsecond unit. (Shasiko review). v5: - Simplify: don't introduce additional redesign and use min_t with a backoff to cap wait. (Rodrigo). v4: - Simplify using poll_timeout_us and poll_timeout_us_atomic and update all callers to never use a param for atomic (Jani) v3: - Use div64_s64 kernel API for 32-bit vs 64-bit division. v2: - Fixed checkpatch failure. - Added helper for 64-bit DIV_ROUND_UP on 32-bit CPU (Shasiko review). Fixed bug max range in usleep_range(Shasiko review) Fixes: 5c09bd6ccd41 ("drm/xe/mmio: Move xe_mmio_wait32() to xe_mmio.c") Signed-off-by: Alan Previn Reviewed-by: Rodrigo Vivi Assisted-by: LLM Link: https://patch.msgid.link/20260929192037.2233429-2-alan.previn.teres.alexis@intel.com Signed-off-by: Rodrigo Vivi (cherry picked from commit 70dab9ee7d620e6018a64798aed065d14e9baed1) Signed-off-by: Rodrigo Vivi Signed-off-by: Sasha Levin --- drivers/gpu/drm/xe/xe_mmio.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c index 6752881af093a..079a707217da7 100644 --- a/drivers/gpu/drm/xe/xe_mmio.c +++ b/drivers/gpu/drm/xe/xe_mmio.c @@ -283,6 +283,7 @@ u64 xe_mmio_read64_2x32(struct xe_mmio *mmio, struct xe_reg reg) return (u64)udw << 32 | ldw; } +#define __XE_MMIO_WAIT_MAX_BACKOFF_100MS (100 * USEC_PER_MSEC) static int __xe_mmio_wait32(struct xe_mmio *mmio, struct xe_reg reg, u32 mask, u32 val, u32 timeout_us, u32 *out_val, bool atomic, bool expect_match) { @@ -313,10 +314,10 @@ static int __xe_mmio_wait32(struct xe_mmio *mmio, struct xe_reg reg, u32 mask, u wait = ktime_us_delta(end, cur); if (atomic) - udelay(wait); + udelay(min_t(s64, wait, (MAX_UDELAY_MS * 1000))); else usleep_range(wait, wait << 1); - wait <<= 1; + wait = min_t(s64, wait << 1, __XE_MMIO_WAIT_MAX_BACKOFF_100MS); } if (ret != 0) { -- 2.53.0