On Mon, Nov 28, 2022 at 09:58:11AM -0800, Alison Schofield wrote: > On Sun, Nov 27, 2022 at 08:03:38PM -0800, Ira Weiny wrote: > > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > Gregory Price and Jonathan Cameron reported a bug within > > pci_doe_submit_task().[1] The issue was that work item initialization > > needs to be done with either INIT_WORK_ONSTACK() or INIT_WORK() > > depending on how the work item is allocated. > > > > Initially, it was anticipated that DOE tasks were going to need to be > > submitted asynchronously and the code was designed thusly. Many > > alternatives were discussed to fix the work initialization issue.[2] > > > > However, all current users submit tasks synchronously and this has > > therefore become an unneeded maintenance burden. Remove the extra > > maintenance burden by replacing asynchronous task submission with > > a synchronous wait function.[3] > > Commit msg: Please look at replacing this: > PCI/DOE: Remove asynchronous task support > with something like this: > PCI/DOE: Replace async task submission with sync wait function Ok yes this makes sense. Thanks for looking! Ira > to more accurately reflect what this patch does. It is not > only removing code. > > Like the first patch, I'm unfamiliar w the details, and am > just expecting that a patch that says 'Remove' doesn't add > anything. > > > > > [1] https://lore.kernel.org/linux-cxl/20221014151045.24781-1-Jonathan.Cameron@xxxxxxxxxx/T/#m88a7f50dcce52f30c8bf5c3dcc06fa9843b54a2d > > [2] https://lore.kernel.org/linux-cxl/Y3kSDQDur+IUDs2O@iweiny-mobl/T/#m0f057773d9c75432fcfcc54a2604483fe82abe92 > > [3] https://lore.kernel.org/linux-cxl/Y3kSDQDur+IUDs2O@iweiny-mobl/T/#m32d3f9b208ef7486bc148d94a326b26b2d3e69ff > > > > Reported-by: Gregory Price <gregory.price@xxxxxxxxxxxx> > > Reported-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx> > > Suggested-by: "Li, Ming" <ming4.li@xxxxxxxxx> > > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > --- > > Changes from V2: > > Jonathan > > Fix comment on struct pci_doe_mb > > Remove signal_task_complete() > > > > Changes from V1: > > Dan Williams: > > Use mutex_lock_interruptible() > > Adjust comment to lock the doe_mb structure not the > > code > > Adjust the locking based on the new series which eliminated > > PCI_DOE_FLAG_CANCEL. > > > > Thanks to Dan for the bulk of the patch. > > Thanks to Ming for pointing out the need for a lock to prevent more > > than 1 task from being processed at a time. > > --- > > drivers/cxl/core/pci.c | 16 ++------ > > drivers/pci/doe.c | 86 +++++++++++++---------------------------- > > include/linux/pci-doe.h | 11 +----- > > 3 files changed, 31 insertions(+), 82 deletions(-) > > > > diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c > > index 9240df53ed87..58977e0712b6 100644 > > --- a/drivers/cxl/core/pci.c > > +++ b/drivers/cxl/core/pci.c > > @@ -490,21 +490,14 @@ static struct pci_doe_mb *find_cdat_doe(struct device *uport) > > CXL_DOE_TABLE_ACCESS_TABLE_TYPE_CDATA) | \ > > FIELD_PREP(CXL_DOE_TABLE_ACCESS_ENTRY_HANDLE, (entry_handle))) > > > > -static void cxl_doe_task_complete(struct pci_doe_task *task) > > -{ > > - complete(task->private); > > -} > > - > > struct cdat_doe_task { > > u32 request_pl; > > u32 response_pl[32]; > > - struct completion c; > > struct pci_doe_task task; > > }; > > > > #define DECLARE_CDAT_DOE_TASK(req, cdt) \ > > struct cdat_doe_task cdt = { \ > > - .c = COMPLETION_INITIALIZER_ONSTACK(cdt.c), \ > > .request_pl = req, \ > > .task = { \ > > .prot.vid = PCI_DVSEC_VENDOR_ID_CXL, \ > > @@ -513,8 +506,6 @@ struct cdat_doe_task cdt = { \ > > .request_pl_sz = sizeof(cdt.request_pl), \ > > .response_pl = cdt.response_pl, \ > > .response_pl_sz = sizeof(cdt.response_pl), \ > > - .complete = cxl_doe_task_complete, \ > > - .private = &cdt.c, \ > > } \ > > } > > > > @@ -525,12 +516,12 @@ static int cxl_cdat_get_length(struct device *dev, > > DECLARE_CDAT_DOE_TASK(CDAT_DOE_REQ(0), t); > > int rc; > > > > - rc = pci_doe_submit_task(cdat_doe, &t.task); > > + rc = pci_doe_submit_task_wait(cdat_doe, &t.task); > > if (rc < 0) { > > dev_err(dev, "DOE submit failed: %d", rc); > > return rc; > > } > > - wait_for_completion(&t.c); > > + > > if (t.task.rv < sizeof(u32)) > > return -EIO; > > > > @@ -554,12 +545,11 @@ static int cxl_cdat_read_table(struct device *dev, > > u32 *entry; > > int rc; > > > > - rc = pci_doe_submit_task(cdat_doe, &t.task); > > + rc = pci_doe_submit_task_wait(cdat_doe, &t.task); > > if (rc < 0) { > > dev_err(dev, "DOE submit failed: %d", rc); > > return rc; > > } > > - wait_for_completion(&t.c); > > /* 1 DW header + 1 DW data min */ > > if (t.task.rv < (2 * sizeof(u32))) > > return -EIO; > > diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c > > index 685e7d26c7eb..b399f0f4fb5d 100644 > > --- a/drivers/pci/doe.c > > +++ b/drivers/pci/doe.c > > @@ -18,7 +18,6 @@ > > #include <linux/mutex.h> > > #include <linux/pci.h> > > #include <linux/pci-doe.h> > > -#include <linux/workqueue.h> > > > > #define PCI_DOE_PROTOCOL_DISCOVERY 0 > > > > @@ -40,7 +39,7 @@ > > * @cap_offset: Capability offset > > * @prots: Array of protocols supported (encoded as long values) > > * @wq: Wait queue for work item > > - * @work_queue: Queue of pci_doe_work items > > + * @lock: Lock state of doe_mb during task processing > > * @flags: Bit array of PCI_DOE_FLAG_* flags > > */ > > struct pci_doe_mb { > > @@ -49,7 +48,7 @@ struct pci_doe_mb { > > struct xarray prots; > > > > wait_queue_head_t wq; > > - struct workqueue_struct *work_queue; > > + struct mutex lock; > > unsigned long flags; > > }; > > > > @@ -196,12 +195,6 @@ static int pci_doe_recv_resp(struct pci_doe_mb *doe_mb, struct pci_doe_task *tas > > return min(length, task->response_pl_sz / sizeof(u32)) * sizeof(u32); > > } > > > > -static void signal_task_complete(struct pci_doe_task *task, int rv) > > -{ > > - task->rv = rv; > > - task->complete(task); > > -} > > - > > static void signal_task_abort(struct pci_doe_task *task, int rv) > > { > > struct pci_doe_mb *doe_mb = task->doe_mb; > > @@ -216,13 +209,11 @@ static void signal_task_abort(struct pci_doe_task *task, int rv) > > doe_mb->cap_offset); > > set_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags); > > } > > - signal_task_complete(task, rv); > > + task->rv = rv; > > } > > > > -static void doe_statemachine_work(struct work_struct *work) > > +static void exec_task(struct pci_doe_task *task) > > { > > - struct pci_doe_task *task = container_of(work, struct pci_doe_task, > > - work); > > struct pci_doe_mb *doe_mb = task->doe_mb; > > struct pci_dev *pdev = doe_mb->pdev; > > int offset = doe_mb->cap_offset; > > @@ -231,7 +222,7 @@ static void doe_statemachine_work(struct work_struct *work) > > int rc; > > > > if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags)) { > > - signal_task_complete(task, -EIO); > > + task->rv = -EIO; > > return; > > } > > > > @@ -276,12 +267,7 @@ static void doe_statemachine_work(struct work_struct *work) > > return; > > } > > > > - signal_task_complete(task, rc); > > -} > > - > > -static void pci_doe_task_complete(struct pci_doe_task *task) > > -{ > > - complete(task->private); > > + task->rv = rc; > > } > > > > static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid, > > @@ -290,7 +276,6 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid, > > u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX, > > *index); > > u32 response_pl; > > - DECLARE_COMPLETION_ONSTACK(c); > > struct pci_doe_task task = { > > .prot.vid = PCI_VENDOR_ID_PCI_SIG, > > .prot.type = PCI_DOE_PROTOCOL_DISCOVERY, > > @@ -298,17 +283,13 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid, > > .request_pl_sz = sizeof(request_pl), > > .response_pl = &response_pl, > > .response_pl_sz = sizeof(response_pl), > > - .complete = pci_doe_task_complete, > > - .private = &c, > > }; > > int rc; > > > > - rc = pci_doe_submit_task(doe_mb, &task); > > + rc = pci_doe_submit_task_wait(doe_mb, &task); > > if (rc < 0) > > return rc; > > > > - wait_for_completion(&c); > > - > > if (task.rv != sizeof(response_pl)) > > return -EIO; > > > > @@ -360,13 +341,6 @@ static void pci_doe_xa_destroy(void *mb) > > xa_destroy(&doe_mb->prots); > > } > > > > -static void pci_doe_destroy_workqueue(void *mb) > > -{ > > - struct pci_doe_mb *doe_mb = mb; > > - > > - destroy_workqueue(doe_mb->work_queue); > > -} > > - > > /** > > * pcim_doe_create_mb() - Create a DOE mailbox object > > * > > @@ -392,25 +366,13 @@ struct pci_doe_mb *pcim_doe_create_mb(struct pci_dev *pdev, u16 cap_offset) > > doe_mb->pdev = pdev; > > doe_mb->cap_offset = cap_offset; > > init_waitqueue_head(&doe_mb->wq); > > + mutex_init(&doe_mb->lock); > > > > xa_init(&doe_mb->prots); > > rc = devm_add_action(dev, pci_doe_xa_destroy, doe_mb); > > if (rc) > > return ERR_PTR(rc); > > > > - doe_mb->work_queue = alloc_ordered_workqueue("%s %s DOE [%x]", 0, > > - dev_driver_string(&pdev->dev), > > - pci_name(pdev), > > - doe_mb->cap_offset); > > - if (!doe_mb->work_queue) { > > - pci_err(pdev, "[%x] failed to allocate work queue\n", > > - doe_mb->cap_offset); > > - return ERR_PTR(-ENOMEM); > > - } > > - rc = devm_add_action_or_reset(dev, pci_doe_destroy_workqueue, doe_mb); > > - if (rc) > > - return ERR_PTR(rc); > > - > > /* Reset the mailbox by issuing an abort */ > > rc = pci_doe_abort(doe_mb); > > if (rc) { > > @@ -457,24 +419,25 @@ bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type) > > EXPORT_SYMBOL_GPL(pci_doe_supports_prot); > > > > /** > > - * pci_doe_submit_task() - Submit a task to be processed by the state machine > > + * pci_doe_submit_task_wait() - Submit and execute a task > > * > > * @doe_mb: DOE mailbox capability to submit to > > - * @task: task to be queued > > - * > > - * Submit a DOE task (request/response) to the DOE mailbox to be processed. > > - * Returns upon queueing the task object. If the queue is full this function > > - * will sleep until there is room in the queue. > > + * @task: task to be run > > * > > - * task->complete will be called when the state machine is done processing this > > - * task. > > + * Submit and run DOE task (request/response) to the DOE mailbox to be > > + * processed. > > * > > * Excess data will be discarded. > > * > > - * RETURNS: 0 when task has been successfully queued, -ERRNO on error > > + * Context: non-interrupt > > + * > > + * RETURNS: 0 when task was executed, the @task->rv holds the status > > + * result of the executed opertion, -ERRNO on failure to submit. > > */ > > -int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task) > > +int pci_doe_submit_task_wait(struct pci_doe_mb *doe_mb, struct pci_doe_task *task) > > { > > + int rc; > > + > > if (!pci_doe_supports_prot(doe_mb, task->prot.vid, task->prot.type)) > > return -EINVAL; > > > > @@ -490,8 +453,13 @@ int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task) > > return -EIO; > > > > task->doe_mb = doe_mb; > > - INIT_WORK(&task->work, doe_statemachine_work); > > - queue_work(doe_mb->work_queue, &task->work); > > + > > + rc = mutex_lock_interruptible(&doe_mb->lock); > > + if (rc) > > + return rc; > > + exec_task(task); > > + mutex_unlock(&doe_mb->lock); > > + > > return 0; > > } > > -EXPORT_SYMBOL_GPL(pci_doe_submit_task); > > +EXPORT_SYMBOL_GPL(pci_doe_submit_task_wait); > > diff --git a/include/linux/pci-doe.h b/include/linux/pci-doe.h > > index ed9b4df792b8..55e6e45b87f3 100644 > > --- a/include/linux/pci-doe.h > > +++ b/include/linux/pci-doe.h > > @@ -29,9 +29,6 @@ struct pci_doe_mb; > > * @response_pl: The response payload > > * @response_pl_sz: Size of the response payload (bytes) > > * @rv: Return value. Length of received response or error (bytes) > > - * @complete: Called when task is complete > > - * @private: Private data for the consumer > > - * @work: Used internally by the mailbox > > * @doe_mb: Used internally by the mailbox > > * > > * The payload sizes and rv are specified in bytes with the following > > @@ -50,11 +47,6 @@ struct pci_doe_task { > > u32 *response_pl; > > size_t response_pl_sz; > > int rv; > > - void (*complete)(struct pci_doe_task *task); > > - void *private; > > - > > - /* No need for the user to initialize these fields */ > > - struct work_struct work; > > struct pci_doe_mb *doe_mb; > > }; > > > > @@ -72,6 +64,5 @@ struct pci_doe_task { > > > > struct pci_doe_mb *pcim_doe_create_mb(struct pci_dev *pdev, u16 cap_offset); > > bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type); > > -int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task); > > - > > +int pci_doe_submit_task_wait(struct pci_doe_mb *doe_mb, struct pci_doe_task *task); > > #endif > > -- > > 2.37.2 > >
