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 <[email protected]>
Reviewed-by: Rodrigo Vivi <[email protected]>
Assisted-by: LLM
---
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 7fa18dfcb5a2..455a07d79cd9 100644
--- a/drivers/gpu/drm/xe/xe_mmio.c
+++ b/drivers/gpu/drm/xe/xe_mmio.c
@@ -320,6 +320,7 @@ 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)
{
@@ -350,10 +351,10 @@ 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) {
--
2.43.0
