[PATCH] firewire: Convert from tasklet to BH workqueue
From: Allen Pais
Date: Wed Apr 03 2024 - 10:47:04 EST
The only generic interface to execute asynchronously in the BH context is
tasklet; however, it's marked deprecated and has some design flaws. To
replace tasklets, BH workqueue support was recently added. A BH workqueue
behaves similarly to regular workqueues except that the queued work items
are executed in the BH context.
This patch converts drivers/firewire/* from tasklet to BH workqueue.
Based on the work done by Tejun Heo <tj@xxxxxxxxxx>
Branch: https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git disable_work-v1
Changes are tested by: @recallmenot
(https://github.com/allenpais/for-6.9-bh-conversions/issues/1)
Signed-off-by: Allen Pais <allen.lkml@xxxxxxxxx>
---
drivers/firewire/ohci.c | 54 ++++++++++++++++++++---------------------
1 file changed, 26 insertions(+), 28 deletions(-)
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 7bc71f4be64a..0c8e73e894e8 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -93,7 +93,7 @@ struct ar_context {
void *pointer;
unsigned int last_buffer_index;
u32 regs;
- struct tasklet_struct tasklet;
+ struct work_struct work;
};
struct context;
@@ -150,7 +150,7 @@ struct context {
descriptor_callback_t callback;
- struct tasklet_struct tasklet;
+ struct work_struct work;
};
#define IT_HEADER_SY(v) ((v) << 0)
@@ -968,9 +968,9 @@ static void ar_recycle_buffers(struct ar_context *ctx, unsigned int end_buffer)
}
}
-static void ar_context_tasklet(unsigned long data)
+static void ar_context_work(struct work_struct *w)
{
- struct ar_context *ctx = (struct ar_context *)data;
+ struct ar_context *ctx = from_work(ctx, w, work);
unsigned int end_buffer_index, end_buffer_offset;
void *p, *end;
@@ -1025,7 +1025,7 @@ static int ar_context_init(struct ar_context *ctx, struct fw_ohci *ohci,
ctx->regs = regs;
ctx->ohci = ohci;
- tasklet_init(&ctx->tasklet, ar_context_tasklet, (unsigned long)ctx);
+ INIT_WORK(&ctx->work, ar_context_work);
for (i = 0; i < AR_BUFFERS; i++) {
ctx->pages[i] = dma_alloc_pages(dev, PAGE_SIZE, &dma_addr,
@@ -1093,9 +1093,9 @@ static struct descriptor *find_branch_descriptor(struct descriptor *d, int z)
return d + z - 1;
}
-static void context_tasklet(unsigned long data)
+static void context_work(struct work_struct *w)
{
- struct context *ctx = (struct context *) data;
+ struct context *ctx = from_work(ctx, w, work);
struct descriptor *d, *last;
u32 address;
int z;
@@ -1188,7 +1188,7 @@ static int context_init(struct context *ctx, struct fw_ohci *ohci,
ctx->buffer_tail = list_entry(ctx->buffer_list.next,
struct descriptor_buffer, list);
- tasklet_init(&ctx->tasklet, context_tasklet, (unsigned long)ctx);
+ INIT_WORK(&ctx->work, context_work);
ctx->callback = callback;
/*
@@ -1460,13 +1460,12 @@ static int at_context_queue_packet(struct context *ctx,
static void at_context_flush(struct context *ctx)
{
- tasklet_disable(&ctx->tasklet);
+ disable_work_sync(&ctx->work);
ctx->flushing = true;
- context_tasklet((unsigned long)ctx);
ctx->flushing = false;
- tasklet_enable(&ctx->tasklet);
+ enable_and_queue_work(system_bh_wq, &ctx->work);
}
static int handle_at_packet(struct context *context,
@@ -2136,16 +2135,16 @@ static irqreturn_t irq_handler(int irq, void *data)
queue_work(selfid_workqueue, &ohci->bus_reset_work);
if (event & OHCI1394_RQPkt)
- tasklet_schedule(&ohci->ar_request_ctx.tasklet);
+ queue_work(system_bh_wq, &ohci->ar_request_ctx.work);
if (event & OHCI1394_RSPkt)
- tasklet_schedule(&ohci->ar_response_ctx.tasklet);
+ queue_work(system_bh_wq, &ohci->ar_response_ctx.work);
if (event & OHCI1394_reqTxComplete)
- tasklet_schedule(&ohci->at_request_ctx.tasklet);
+ queue_work(system_bh_wq, &ohci->at_request_ctx.work);
if (event & OHCI1394_respTxComplete)
- tasklet_schedule(&ohci->at_response_ctx.tasklet);
+ queue_work(system_bh_wq, &ohci->at_response_ctx.work);
if (event & OHCI1394_isochRx) {
iso_event = reg_read(ohci, OHCI1394_IsoRecvIntEventClear);
@@ -2153,8 +2152,8 @@ static irqreturn_t irq_handler(int irq, void *data)
while (iso_event) {
i = ffs(iso_event) - 1;
- tasklet_schedule(
- &ohci->ir_context_list[i].context.tasklet);
+ queue_work(system_bh_wq,
+ &ohci->ir_context_list[i].context.work);
iso_event &= ~(1 << i);
}
}
@@ -2165,8 +2164,8 @@ static irqreturn_t irq_handler(int irq, void *data)
while (iso_event) {
i = ffs(iso_event) - 1;
- tasklet_schedule(
- &ohci->it_context_list[i].context.tasklet);
+ queue_work(system_bh_wq,
+ &ohci->it_context_list[i].context.work);
iso_event &= ~(1 << i);
}
}
@@ -2431,7 +2430,7 @@ static int ohci_enable(struct fw_card *card,
* They shouldn't do that in this initial case where the link
* isn't enabled. This means we have to use the same
* workaround here, setting the bus header to 0 and then write
- * the right values in the bus reset tasklet.
+ * the right values in the bus reset work.
*/
if (config_rom) {
@@ -2521,7 +2520,7 @@ static int ohci_set_config_rom(struct fw_card *card,
* during the atomic update, even on litte endian
* architectures. The workaround we use is to put a 0 in the
* header quadlet; 0 is endian agnostic and means that the
- * config rom isn't ready yet. In the bus reset tasklet we
+ * config rom isn't ready yet. In the bus reset work we
* then set up the real values for the two registers.
*
* We use ohci->lock to avoid racing with the code that sets
@@ -2570,7 +2569,7 @@ static int ohci_set_config_rom(struct fw_card *card,
/*
* Now initiate a bus reset to have the changes take
* effect. We clean up the old config rom memory and DMA
- * mappings in the bus reset tasklet, since the OHCI
+ * mappings in the bus reset work, since the OHCI
* controller could need to access it before the bus reset
* takes effect.
*/
@@ -2601,7 +2600,7 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet)
struct driver_data *driver_data = packet->driver_data;
int ret = -ENOENT;
- tasklet_disable_in_atomic(&ctx->tasklet);
+ disable_work_sync(&ctx->work);
if (packet->ack != 0)
goto out;
@@ -2620,7 +2619,7 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet)
packet->callback(packet, &ohci->card, packet->ack);
ret = 0;
out:
- tasklet_enable(&ctx->tasklet);
+ enable_and_queue_work(system_bh_wq, &ctx->work);
return ret;
}
@@ -3153,7 +3152,7 @@ static int ohci_stop_iso(struct fw_iso_context *base)
}
flush_writes(ohci);
context_stop(&ctx->context);
- tasklet_kill(&ctx->context.tasklet);
+ cancel_work_sync(&ctx->context.work);
return 0;
}
@@ -3525,10 +3524,9 @@ static int ohci_flush_iso_completions(struct fw_iso_context *base)
struct iso_context *ctx = container_of(base, struct iso_context, base);
int ret = 0;
- tasklet_disable_in_atomic(&ctx->context.tasklet);
+ disable_work_sync(&ctx->context.work);
if (!test_and_set_bit_lock(0, &ctx->flushing_completions)) {
- context_tasklet((unsigned long)&ctx->context);
switch (base->type) {
case FW_ISO_CONTEXT_TRANSMIT:
@@ -3548,7 +3546,7 @@ static int ohci_flush_iso_completions(struct fw_iso_context *base)
smp_mb__after_atomic();
}
- tasklet_enable(&ctx->context.tasklet);
+ enable_and_queue_work(system_bh_wq, &ctx->context.work);
return ret;
}
--
2.17.1