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 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 >
