This is a note to let you know that I've just added the patch titled
dmaengine: idxd: Remove shadow Event Log head stored in idxd
to the 6.7-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:
dmaengine-idxd-remove-shadow-event-log-head-stored-i.patch
and it can be found in the queue-6.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0eb7bf1b4ffe668dc64b2e9f7435a0143b218626
Author: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Date: Wed Feb 14 18:49:31 2024 -0800
dmaengine: idxd: Remove shadow Event Log head stored in idxd
[ Upstream commit ecec7c9f29a7114a3e23a14020b1149ea7dffb4f ]
head is defined in idxd->evl as a shadow of head in the EVLSTATUS register.
There are two issues related to the shadow head:
1. Mismatch between the shadow head and the state of the EVLSTATUS
register:
If Event Log is supported, upon completion of the Enable Device command,
the Event Log head in the variable idxd->evl->head should be cleared to
match the state of the EVLSTATUS register. But the variable is not reset
currently, leading mismatch between the variable and the register state.
The mismatch causes incorrect processing of Event Log entries.
2. Unnecessary shadow head definition:
The shadow head is unnecessary as head can be read directly from the
EVLSTATUS register. Reading head from the register incurs no additional
cost because event log head and tail are always read together and
tail is already read directly from the register as required by hardware.
Remove the shadow Event Log head stored in idxd->evl to address the
mentioned issues.
Fixes: 244da66cda35 ("dmaengine: idxd: setup event log configuration")
Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240215024931.1739621-1-fenghua.yu@xxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index 0423655f5a880..3dd25a9a04f18 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -345,7 +345,7 @@ static void idxd_cdev_evl_drain_pasid(struct idxd_wq *wq, u32 pasid)
spin_lock(&evl->lock);
status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
t = status.tail;
- h = evl->head;
+ h = status.head;
size = evl->size;
while (h != t) {
diff --git a/drivers/dma/idxd/debugfs.c b/drivers/dma/idxd/debugfs.c
index 9cfbd9b14c4c4..f3f25ee676f30 100644
--- a/drivers/dma/idxd/debugfs.c
+++ b/drivers/dma/idxd/debugfs.c
@@ -68,9 +68,9 @@ static int debugfs_evl_show(struct seq_file *s, void *d)
spin_lock(&evl->lock);
- h = evl->head;
evl_status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
t = evl_status.tail;
+ h = evl_status.head;
evl_size = evl->size;
seq_printf(s, "Event Log head %u tail %u interrupt pending %u\n\n",
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 1e89c80a07fc2..96062ae39f9a2 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -290,7 +290,6 @@ struct idxd_evl {
unsigned int log_size;
/* The number of entries in the event log. */
u16 size;
- u16 head;
unsigned long *bmap;
bool batch_fail[IDXD_MAX_BATCH_IDENT];
};
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 2183d7f9cdbdd..3bdfc1797f620 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -367,9 +367,9 @@ static void process_evl_entries(struct idxd_device *idxd)
/* Clear interrupt pending bit */
iowrite32(evl_status.bits_upper32,
idxd->reg_base + IDXD_EVLSTATUS_OFFSET + sizeof(u32));
- h = evl->head;
evl_status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
t = evl_status.tail;
+ h = evl_status.head;
size = idxd->evl->size;
while (h != t) {
@@ -378,7 +378,6 @@ static void process_evl_entries(struct idxd_device *idxd)
h = (h + 1) % size;
}
- evl->head = h;
evl_status.head = h;
iowrite32(evl_status.bits_lower32, idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
spin_unlock(&evl->lock);
