From patchwork Tue Nov 14 21:16:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 13455964 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EE2193306F for ; Tue, 14 Nov 2023 21:18:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from mail-pl1-f180.google.com (mail-pl1-f180.google.com [209.85.214.180]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E1DFC3; Tue, 14 Nov 2023 13:18:27 -0800 (PST) Received: by mail-pl1-f180.google.com with SMTP id d9443c01a7336-1cc30bf9e22so1757245ad.1; Tue, 14 Nov 2023 13:18:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1699996707; x=1700601507; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=S4050Df3wVHg7KTGgS7dsrp4UQxEW02D6+iCI7Hka50=; b=f767J7XoN3AbLztMIm3l9a6cKPFzFsB31FImQOeVHq3XSGh8S3fbkop9fp5/C9jxia 92k4kQw9uoJxA2wRZ0FfjS2nhoo8PvroAnt7Osvhj89vCH3sidkO49W39+tUj1Y6uYCB SvtG8WWoIRa8phQ3lF1286l9zVORRgVn09WYSbAFkPjDz8OKuIY6Q1V3aFwpVVsXiiV0 sqe+xzgjEVOUwvrHLdSyNmmXZ270F2H9a0ZsNOLXnvu4bf/nxu0DonEDkiPQWEItweKH X6FRZxGbQJ28E35GKeo90VEsfeQy+K+p6ZZ4ze55Vt9FELaSlSPqHQNYeLFZUk7m6kSm c+xQ== X-Gm-Message-State: AOJu0Yyd49OEGk/N1S7w6aFLILwEWsQ/sFGlEIscBaSCJq3G5Rl5OTje 1tVbFBHZAx+3G/OafBurexw= X-Google-Smtp-Source: AGHT+IFUEGs3c9fwcpw04I5xr9zni4VLuz/t0KQFPwlMkw82wMsPfhCbYmM+D4qGppL4TGN40sh2KQ== X-Received: by 2002:a17:902:8216:b0:1ce:1b7b:8396 with SMTP id x22-20020a170902821600b001ce1b7b8396mr4018537pln.29.1699996706899; Tue, 14 Nov 2023 13:18:26 -0800 (PST) Received: from bvanassche-linux.mtv.corp.google.com ([2620:0:1000:8411:2278:ad72:cefb:4d49]) by smtp.gmail.com with ESMTPSA id ix7-20020a170902f80700b001c71ec1866fsm6169288plb.258.2023.11.14.13.18.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Nov 2023 13:18:26 -0800 (PST) From: Bart Van Assche To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, Jens Axboe , Christoph Hellwig , Bart Van Assche , Damien Le Moal , Ming Lei , "James E.J. Bottomley" Subject: [PATCH v15 06/19] scsi: core: Introduce a mechanism for reordering requests in the error handler Date: Tue, 14 Nov 2023 13:16:14 -0800 Message-ID: <20231114211804.1449162-7-bvanassche@acm.org> X-Mailer: git-send-email 2.43.0.rc0.421.g78406f8d94-goog In-Reply-To: <20231114211804.1449162-1-bvanassche@acm.org> References: <20231114211804.1449162-1-bvanassche@acm.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Introduce the .eh_needs_prepare_resubmit and the .eh_prepare_resubmit function pointers in struct scsi_driver. Make the error handler call .eh_prepare_resubmit() before resubmitting commands if any of the .eh_needs_prepare_resubmit() invocations return true. A later patch will use this functionality to sort SCSI commands by LBA from inside the SCSI disk driver before these are resubmitted by the error handler. Reviewed-by: Damien Le Moal Cc: Martin K. Petersen Cc: Christoph Hellwig Cc: Ming Lei Signed-off-by: Bart Van Assche --- drivers/scsi/scsi_error.c | 51 ++++++++++++++++++++++++++++++++++++++ include/scsi/scsi_driver.h | 1 + include/scsi/scsi_host.h | 6 +++++ 3 files changed, 58 insertions(+) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 7390131e7f0a..4214d7b79b06 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -2186,6 +2187,54 @@ void scsi_eh_ready_devs(struct Scsi_Host *shost, } EXPORT_SYMBOL_GPL(scsi_eh_ready_devs); +/* + * Comparison function for sorting SCSI commands by ULD driver. + */ +static int scsi_cmp_uld(void *priv, const struct list_head *_a, + const struct list_head *_b) +{ + struct scsi_cmnd *a = list_entry(_a, typeof(*a), eh_entry); + struct scsi_cmnd *b = list_entry(_b, typeof(*b), eh_entry); + + /* See also the comment above the list_sort() definition. */ + return scsi_cmd_to_driver(a) > scsi_cmd_to_driver(b); +} + +static void scsi_call_prepare_resubmit(struct Scsi_Host *shost, + struct list_head *done_q) +{ + struct scsi_cmnd *scmd, *next; + + if (!shost->hostt->needs_prepare_resubmit) + return; + + if (list_empty(done_q)) + return; + + /* Sort pending SCSI commands by ULD. */ + list_sort(NULL, done_q, scsi_cmp_uld); + + /* + * Call .eh_prepare_resubmit for each range of commands with identical + * ULD driver pointer. + */ + list_for_each_entry_safe(scmd, next, done_q, eh_entry) { + struct scsi_driver *uld = + scmd->device ? scsi_cmd_to_driver(scmd) : NULL; + struct list_head *prev, uld_cmd_list; + + while (&next->eh_entry != done_q && + scsi_cmd_to_driver(next) == uld) + next = list_next_entry(next, eh_entry); + if (!uld->eh_prepare_resubmit) + continue; + prev = scmd->eh_entry.prev; + list_cut_position(&uld_cmd_list, prev, next->eh_entry.prev); + uld->eh_prepare_resubmit(&uld_cmd_list); + list_splice(&uld_cmd_list, prev); + } +} + /** * scsi_eh_flush_done_q - finish processed commands or retry them. * @shost: SCSI host pointer. @@ -2195,6 +2244,8 @@ void scsi_eh_flush_done_q(struct Scsi_Host *shost, struct list_head *done_q) { struct scsi_cmnd *scmd, *next; + scsi_call_prepare_resubmit(shost, done_q); + list_for_each_entry_safe(scmd, next, done_q, eh_entry) { list_del_init(&scmd->eh_entry); if (scsi_device_online(scmd->device) && diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h index 4ce1988b2ba0..2b11be896eee 100644 --- a/include/scsi/scsi_driver.h +++ b/include/scsi/scsi_driver.h @@ -18,6 +18,7 @@ struct scsi_driver { int (*done)(struct scsi_cmnd *); int (*eh_action)(struct scsi_cmnd *, int); void (*eh_reset)(struct scsi_cmnd *); + void (*eh_prepare_resubmit)(struct list_head *cmd_list); }; #define to_scsi_driver(drv) \ container_of((drv), struct scsi_driver, gendrv) diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 3b907fc2ef08..150ae619c4d2 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -464,6 +464,12 @@ struct scsi_host_template { /* The queuecommand callback may block. See also BLK_MQ_F_BLOCKING. */ unsigned queuecommand_may_block:1; + /* + * The scsi_driver .eh_prepare_resubmit function must be called by + * the SCSI error handler. + */ + unsigned needs_prepare_resubmit:1; + /* * Countdown for host blocking with no commands outstanding. */