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[79.52.107.152]) by smtp.gmail.com with ESMTPSA id z11sm1404698ejc.122.2021.05.04.06.32.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 May 2021 06:32:57 -0700 (PDT) From: "Fabio M. De Francesco" To: outreachy-kernel@googlegroups.com, David Kershner , Greg Kroah-Hartman , sparmaintainer@unisys.com, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, Matthew Wilcox , Daniel Vetter , Dan Carpenter Cc: "Fabio M. De Francesco" Subject: [PATCH v7] staging: unisys: visorhba: Convert module from IDR to XArray Date: Tue, 4 May 2021 15:32:53 +0200 Message-Id: <20210504133253.32269-1-fmdefrancesco@gmail.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Converted visorhba from IDR to XArray. The abstract data type XArray is more memory-efficient, parallelizable and cache friendly. It takes advantage of RCU to perform lookups without locking. Furthermore, IDR is deprecated because XArray has a better (cleaner and more consistent) API. Signed-off-by: Fabio M. De Francesco --- Changes from v6; Added a call to xa_destroy() that I had forgotten. Fixed taking locks with interrupts disabled (use xa_erase_irq()). Replaced checking for success with checking for failure. Issues detected by Dan Carpenter and Matthew Wilcox. Changes from v5: As suggested by Matthew Wilcox, reworded the commit message, modified setup_scsitaskmgmt_handles() to manage and return errors, used 'xa_limit_32b' as the range of indexes (because there is no need to use 0 as a marker of no allocation). Changes from v4: Fixed some issues detected by Matthew Wilcox and Fabio Aiuto. Changes from v3: Matthew Wilcox found that the XArray was not initialized: now it is. Changed types handles from u64 to u32 because they can't work as arguments of xa_alloc_irq() and u32 is enough large for storing XArray indexes. Changes from v2: Some residual errors from v1 were not fixed in v2. Now they have been removed. Changes from v1: After a first review by Matthew Wilcox, who found a series of errors and gave suggestions on how to fix them, I rewrote a larger part of the patch. .../staging/unisys/visorhba/visorhba_main.c | 102 ++++++++---------- 1 file changed, 43 insertions(+), 59 deletions(-) diff --git a/drivers/staging/unisys/visorhba/visorhba_main.c b/drivers/staging/unisys/visorhba/visorhba_main.c index 4455d26f7c96..61b2b133ec33 100644 --- a/drivers/staging/unisys/visorhba/visorhba_main.c +++ b/drivers/staging/unisys/visorhba/visorhba_main.c @@ -6,10 +6,10 @@ #include #include -#include #include #include #include +#include #include #include #include @@ -82,8 +82,7 @@ struct visorhba_devdata { * allows us to pass int handles back-and-forth between us and * iovm, instead of raw pointers */ - struct idr idr; - + struct xarray xa; struct dentry *debugfs_dir; struct dentry *debugfs_info; }; @@ -182,71 +181,49 @@ static struct uiscmdrsp *get_scsipending_cmdrsp(struct visorhba_devdata *ddata, return NULL; } -/* - * simple_idr_get - Associate a provided pointer with an int value - * 1 <= value <= INT_MAX, and return this int value; - * the pointer value can be obtained later by passing - * this int value to idr_find() - * @idrtable: The data object maintaining the pointer<-->int mappings - * @p: The pointer value to be remembered - * @lock: A spinlock used when exclusive access to idrtable is needed - * - * Return: The id number mapped to pointer 'p', 0 on failure - */ -static unsigned int simple_idr_get(struct idr *idrtable, void *p, - spinlock_t *lock) -{ - int id; - unsigned long flags; - - idr_preload(GFP_KERNEL); - spin_lock_irqsave(lock, flags); - id = idr_alloc(idrtable, p, 1, INT_MAX, GFP_NOWAIT); - spin_unlock_irqrestore(lock, flags); - idr_preload_end(); - /* failure */ - if (id < 0) - return 0; - /* idr_alloc() guarantees > 0 */ - return (unsigned int)(id); -} - /* * setup_scsitaskmgmt_handles - Stash the necessary handles so that the * completion processing logic for a taskmgmt * cmd will be able to find who to wake up * and where to stash the result - * @idrtable: The data object maintaining the pointer<-->int mappings - * @lock: A spinlock used when exclusive access to idrtable is needed + * @xa: The data object maintaining the pointer<-->int mappings * @cmdrsp: Response from the IOVM * @event: The event handle to associate with an id * @result: The location to place the result of the event handle into */ -static void setup_scsitaskmgmt_handles(struct idr *idrtable, spinlock_t *lock, - struct uiscmdrsp *cmdrsp, +static int setup_scsitaskmgmt_handles(struct xarray *xa, struct uiscmdrsp *cmdrsp, wait_queue_head_t *event, int *result) { - /* specify the event that has to be triggered when this */ - /* cmd is complete */ - cmdrsp->scsitaskmgmt.notify_handle = - simple_idr_get(idrtable, event, lock); - cmdrsp->scsitaskmgmt.notifyresult_handle = - simple_idr_get(idrtable, result, lock); + int ret; + u32 id; + + /* specify the event that has to be triggered when this cmd is complete */ + ret = xa_alloc_irq(xa, &id, event, xa_limit_32b, GFP_KERNEL); + if (ret) + return ret; + else + cmdrsp->scsitaskmgmt.notify_handle = id; + ret = xa_alloc_irq(xa, &id, result, xa_limit_32b, GFP_KERNEL); + if (ret) { + xa_erase_irq(xa, cmdrsp->scsitaskmgmt.notify_handle); + return ret; + } else + cmdrsp->scsitaskmgmt.notifyresult_handle = id; + + return 0; } /* * cleanup_scsitaskmgmt_handles - Forget handles created by * setup_scsitaskmgmt_handles() - * @idrtable: The data object maintaining the pointer<-->int mappings + * @xa: The data object maintaining the pointer<-->int mappings * @cmdrsp: Response from the IOVM */ -static void cleanup_scsitaskmgmt_handles(struct idr *idrtable, +static void cleanup_scsitaskmgmt_handles(struct xarray *xa, struct uiscmdrsp *cmdrsp) { - if (cmdrsp->scsitaskmgmt.notify_handle) - idr_remove(idrtable, cmdrsp->scsitaskmgmt.notify_handle); - if (cmdrsp->scsitaskmgmt.notifyresult_handle) - idr_remove(idrtable, cmdrsp->scsitaskmgmt.notifyresult_handle); + xa_erase_irq(xa, cmdrsp->scsitaskmgmt.notify_handle); + xa_erase_irq(xa, cmdrsp->scsitaskmgmt.notifyresult_handle); } /* @@ -269,6 +246,7 @@ static int forward_taskmgmt_command(enum task_mgmt_types tasktype, int notifyresult = 0xffff; wait_queue_head_t notifyevent; int scsicmd_id; + int ret; if (devdata->serverdown || devdata->serverchangingstate) return FAILED; @@ -284,8 +262,14 @@ static int forward_taskmgmt_command(enum task_mgmt_types tasktype, /* issue TASK_MGMT_ABORT_TASK */ cmdrsp->cmdtype = CMD_SCSITASKMGMT_TYPE; - setup_scsitaskmgmt_handles(&devdata->idr, &devdata->privlock, cmdrsp, - ¬ifyevent, ¬ifyresult); + + ret = setup_scsitaskmgmt_handles(&devdata->xa, cmdrsp, + ¬ifyevent, ¬ifyresult); + if (ret) { + dev_dbg(&scsidev->sdev_gendev, + "visorhba: setup_scsitaskmgmt_handles returned %d\n", ret); + return FAILED; + } /* save destination */ cmdrsp->scsitaskmgmt.tasktype = tasktype; @@ -311,14 +295,14 @@ static int forward_taskmgmt_command(enum task_mgmt_types tasktype, dev_dbg(&scsidev->sdev_gendev, "visorhba: taskmgmt type=%d success; result=0x%x\n", tasktype, notifyresult); - cleanup_scsitaskmgmt_handles(&devdata->idr, cmdrsp); + cleanup_scsitaskmgmt_handles(&devdata->xa, cmdrsp); return SUCCESS; err_del_scsipending_ent: dev_dbg(&scsidev->sdev_gendev, "visorhba: taskmgmt type=%d not executed\n", tasktype); del_scsipending_ent(devdata, scsicmd_id); - cleanup_scsitaskmgmt_handles(&devdata->idr, cmdrsp); + cleanup_scsitaskmgmt_handles(&devdata->xa, cmdrsp); return FAILED; } @@ -654,13 +638,13 @@ DEFINE_SHOW_ATTRIBUTE(info_debugfs); * Service Partition returned the result of the task management * command. Wake up anyone waiting for it. */ -static void complete_taskmgmt_command(struct idr *idrtable, +static void complete_taskmgmt_command(struct xarray *xa, struct uiscmdrsp *cmdrsp, int result) { wait_queue_head_t *wq = - idr_find(idrtable, cmdrsp->scsitaskmgmt.notify_handle); + xa_load(xa, cmdrsp->scsitaskmgmt.notify_handle); int *scsi_result_ptr = - idr_find(idrtable, cmdrsp->scsitaskmgmt.notifyresult_handle); + xa_load(xa, cmdrsp->scsitaskmgmt.notifyresult_handle); if (unlikely(!(wq && scsi_result_ptr))) { pr_err("visorhba: no completion context; cmd will time out\n"); return; @@ -708,7 +692,7 @@ static void visorhba_serverdown_complete(struct visorhba_devdata *devdata) break; case CMD_SCSITASKMGMT_TYPE: cmdrsp = pendingdel->sent; - complete_taskmgmt_command(&devdata->idr, cmdrsp, + complete_taskmgmt_command(&devdata->xa, cmdrsp, TASK_MGMT_FAILED); break; default: @@ -905,7 +889,7 @@ static void drain_queue(struct uiscmdrsp *cmdrsp, if (!del_scsipending_ent(devdata, cmdrsp->scsitaskmgmt.handle)) break; - complete_taskmgmt_command(&devdata->idr, cmdrsp, + complete_taskmgmt_command(&devdata->xa, cmdrsp, cmdrsp->scsitaskmgmt.result); } else if (cmdrsp->cmdtype == CMD_NOTIFYGUEST_TYPE) dev_err_once(&devdata->dev->device, @@ -1053,7 +1037,7 @@ static int visorhba_probe(struct visor_device *dev) if (err) goto err_debugfs_info; - idr_init(&devdata->idr); + xa_init(&devdata->xa); devdata->cmdrsp = kmalloc(sizeof(*devdata->cmdrsp), GFP_ATOMIC); visorbus_enable_channel_interrupts(dev); @@ -1096,7 +1080,7 @@ static void visorhba_remove(struct visor_device *dev) scsi_remove_host(scsihost); scsi_host_put(scsihost); - idr_destroy(&devdata->idr); + xa_destroy(&devdata->xa); dev_set_drvdata(&dev->device, NULL); debugfs_remove(devdata->debugfs_info); -- 2.31.1