Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933172AbZJNNnd (ORCPT ); Wed, 14 Oct 2009 09:43:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933119AbZJNNnc (ORCPT ); Wed, 14 Oct 2009 09:43:32 -0400 Received: from ernst.netinsight.se ([194.16.221.21]:33706 "HELO ernst.netinsight.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S933113AbZJNNnb convert rfc822-to-8bit (ORCPT ); Wed, 14 Oct 2009 09:43:31 -0400 Date: Wed, 14 Oct 2009 15:41:24 +0200 From: Simon Kagstrom To: Linus Torvalds , linux-mtd Cc: Ingo Molnar , Andrew Morton , Artem Bityutskiy , David Woodhouse , LKML , "Koskinen Aaro (Nokia-D/Helsinki)" , Alan Cox Subject: [PATCH v6 5/5]: mtdoops: refactor as a kmsg_dumper Message-ID: <20091014154124.5d9c366e@marrow.netinsight.se> In-Reply-To: <20091014153458.05e31db6@marrow.netinsight.se> References: <20091012113758.GB11035@elte.hu> <20091012140149.6789efab@marrow.netinsight.se> <20091012120951.GA16799@elte.hu> <1255349748.10605.13.camel@macbook.infradead.org> <20091012122023.GA19365@elte.hu> <20091012150650.51a4b4dc@marrow.netinsight.se> <20091012131528.GC25464@elte.hu> <20091012153937.0dcd73e5@marrow.netinsight.se> <20091012110954.67d7d8d8.akpm@linux-foundation.org> <20091012182346.GH17138@elte.hu> <20091014153458.05e31db6@marrow.netinsight.se> X-Mailer: Claws Mail 3.7.3 (GTK+ 2.16.1; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11622 Lines: 393 The last messages which happens before a crash might contain interesting information about the crash. This patch reworks mtdoops using the kmsg_dumper support instead of a console, which simplifies the code and also includes the messages before the oops started. On oops callbacks, the MTD device write is scheduled in a work queue (to be able to use the regular mtd->write call), while panics call mtd->panic_write directly. Thus, if panic_on_oops is set, the oops will be written out during the panic. A parameter to specify which mtd device to use (number or name), as well as a flag, writable at runtime, to toggle wheter to dump oopses or only panics (since oopses can often be handled by regular syslog). Signed-off-by: Simon Kagstrom Reviewed-by: Anders Grafstrom --- ChangeLog: Review comments from Anders Grafström and myself: * Fix mtddev and dump_oops parameter permissions (dump_oops is now runtime-settable) * Style cleanup here and there * Add a MTDOOPS_HEADER_SIZE define instead of hardcoding the size * Fix a double-free on unregistration * Rework the patch according to patch 4 * Fix output problems for some conditions drivers/mtd/mtdoops.c | 207 ++++++++++++++++++++----------------------------- 1 files changed, 84 insertions(+), 123 deletions(-) diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 2870a11..817265d 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -29,18 +29,31 @@ #include #include #include -#include #include #include +#include #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00 +#define MTDOOPS_HEADER_SIZE 8 static unsigned long record_size = 4096; module_param(record_size, ulong, 0400); MODULE_PARM_DESC(record_size, "record size for MTD OOPS pages in bytes (default 4096)"); +static char mtddev[80]; +module_param_string(mtddev, mtddev, 80, 0400); +MODULE_PARM_DESC(mtddev, + "name or index number of the MTD device to use"); + +static int dump_oops = 1; +module_param(dump_oops, int, 0600); +MODULE_PARM_DESC(dump_oops, + "set to 1 to dump oopses, 0 to only dump panics (default 1)"); + static struct mtdoops_context { + struct kmsg_dumper dump; + int mtd_index; struct work_struct work_erase; struct work_struct work_write; @@ -49,14 +62,9 @@ static struct mtdoops_context { int nextpage; int nextcount; unsigned long *oops_page_used; - char *name; + const char *name; void *oops_buf; - - /* writecount and disabling ready are spin lock protected */ - spinlock_t writecount_lock; - int ready; - int writecount; } oops_cxt; static void mark_page_used(struct mtdoops_context *cxt, int page) @@ -138,7 +146,6 @@ static void mtdoops_inc_counter(struct mtdoops_context *cxt) printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n", cxt->nextpage, cxt->nextcount); - cxt->ready = 1; } /* Scheduled work - when we can't proceed without erasing a block */ @@ -187,7 +194,6 @@ badblock: if (ret >= 0) { printk(KERN_DEBUG "mtdoops: ready %d, %d\n", cxt->nextpage, cxt->nextcount); - cxt->ready = 1; return; } @@ -205,11 +211,13 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic) { struct mtd_info *mtd = cxt->mtd; size_t retlen; + u32 *hdr; int ret; - if (cxt->writecount < record_size) - memset(cxt->oops_buf + cxt->writecount, 0xff, - record_size - cxt->writecount); + /* Add mtdoops header to the buffer */ + hdr = cxt->oops_buf; + hdr[0] = cxt->nextcount; + hdr[1] = MTDOOPS_KERNMSG_MAGIC; if (panic) ret = mtd->panic_write(mtd, cxt->nextpage * record_size, @@ -218,17 +226,15 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic) ret = mtd->write(mtd, cxt->nextpage * record_size, record_size, &retlen, cxt->oops_buf); - cxt->writecount = 0; - if (retlen != record_size || ret < 0) printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n", cxt->nextpage * record_size, retlen, record_size, ret); mark_page_used(cxt, cxt->nextpage); + memset(cxt->oops_buf, 0xff, record_size); mtdoops_inc_counter(cxt); } - static void mtdoops_workfunc_write(struct work_struct *work) { struct mtdoops_context *cxt = @@ -247,10 +253,13 @@ static void find_next_position(struct mtdoops_context *cxt) for (page = 0; page < cxt->oops_pages; page++) { /* Assume the page is used */ mark_page_used(cxt, page); - ret = mtd->read(mtd, page * record_size, 8, &retlen, (u_char *) &count[0]); - if (retlen != 8 || (ret < 0 && ret != -EUCLEAN)) { - printk(KERN_ERR "mtdoops: read failure at %ld (%td of 8 read), err %d\n", - page * record_size, retlen, ret); + ret = mtd->read(mtd, page * record_size, MTDOOPS_HEADER_SIZE, + &retlen, (u_char *) &count[0]); + if (retlen != MTDOOPS_HEADER_SIZE || + (ret < 0 && ret != -EUCLEAN)) { + printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", + page * record_size, retlen, + MTDOOPS_HEADER_SIZE, ret); continue; } @@ -287,7 +296,6 @@ static void find_next_position(struct mtdoops_context *cxt) } else { printk(KERN_DEBUG "mtdoops: ready %d, %d (clean)\n", cxt->nextpage, cxt->nextcount); - cxt->ready = 1; } return; } @@ -298,6 +306,41 @@ static void find_next_position(struct mtdoops_context *cxt) mtdoops_inc_counter(cxt); } +static void mtdoops_do_dump(struct kmsg_dumper *dump, + enum kmsg_dump_reason reason, const char *s1, unsigned long l1, + const char *s2, unsigned long l2) +{ + struct mtdoops_context *cxt = dump->priv; + unsigned long s1_start, s2_start; + unsigned long l1_cpy, l2_cpy; + char *dst; + + /* Only dump oopses if dump_oops is set */ + if (reason == kmsg_dump_oops && !dump_oops) + return; + + dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */ + l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE); + l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy); + + s2_start = l2 - l2_cpy; + s1_start = l1 - l1_cpy; + + memcpy(dst, s1 + s1_start, l1_cpy); + memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); + + /* Panics must be written immediately */ + if (reason == kmsg_dump_panic) { + if (!cxt->mtd->panic_write) + printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); + else + mtdoops_write(cxt, 1); + return; + } + + /* For other cases, schedule work to write it "nicely" */ + schedule_work(&cxt->work_write); +} static void mtdoops_notify_add(struct mtd_info *mtd) { @@ -339,6 +382,8 @@ static void mtdoops_notify_add(struct mtd_info *mtd) find_next_position(cxt); + cxt->dump.dump = mtdoops_do_dump; + register_kmsg_dumper(&cxt->dump, cxt); printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); } @@ -349,116 +394,27 @@ static void mtdoops_notify_remove(struct mtd_info *mtd) if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) return; + unregister_kmsg_dumper(&cxt->dump); cxt->mtd = NULL; flush_scheduled_work(); } -static void mtdoops_console_sync(void) -{ - struct mtdoops_context *cxt = &oops_cxt; - struct mtd_info *mtd = cxt->mtd; - unsigned long flags; - - if (!cxt->ready || !mtd || cxt->writecount == 0) - return; - - /* - * Once ready is 0 and we've held the lock no further writes to the - * buffer will happen - */ - spin_lock_irqsave(&cxt->writecount_lock, flags); - if (!cxt->ready) { - spin_unlock_irqrestore(&cxt->writecount_lock, flags); - return; - } - cxt->ready = 0; - spin_unlock_irqrestore(&cxt->writecount_lock, flags); - - if (mtd->panic_write && (in_interrupt() || panic_on_oops)) - /* Interrupt context, we're going to panic so try and log */ - mtdoops_write(cxt, 1); - else - schedule_work(&cxt->work_write); -} - -static void -mtdoops_console_write(struct console *co, const char *s, unsigned int count) -{ - struct mtdoops_context *cxt = co->data; - struct mtd_info *mtd = cxt->mtd; - unsigned long flags; - - if (!oops_in_progress) { - mtdoops_console_sync(); - return; - } - - if (!cxt->ready || !mtd) - return; - - /* Locking on writecount ensures sequential writes to the buffer */ - spin_lock_irqsave(&cxt->writecount_lock, flags); - - /* Check ready status didn't change whilst waiting for the lock */ - if (!cxt->ready) { - spin_unlock_irqrestore(&cxt->writecount_lock, flags); - return; - } - - if (cxt->writecount == 0) { - u32 *stamp = cxt->oops_buf; - *stamp++ = cxt->nextcount; - *stamp = MTDOOPS_KERNMSG_MAGIC; - cxt->writecount = 8; - } - - if (count + cxt->writecount > record_size) - count = record_size - cxt->writecount; - - memcpy(cxt->oops_buf + cxt->writecount, s, count); - cxt->writecount += count; - - spin_unlock_irqrestore(&cxt->writecount_lock, flags); - - if (cxt->writecount == record_size) - mtdoops_console_sync(); -} - -static int __init mtdoops_console_setup(struct console *co, char *options) -{ - struct mtdoops_context *cxt = co->data; - - if (cxt->mtd_index != -1 || cxt->name) - return -EBUSY; - if (options) { - cxt->name = kstrdup(options, GFP_KERNEL); - return 0; - } - if (co->index == -1) - return -EINVAL; - - cxt->mtd_index = co->index; - return 0; -} static struct mtd_notifier mtdoops_notifier = { .add = mtdoops_notify_add, .remove = mtdoops_notify_remove, }; -static struct console mtdoops_console = { - .name = "ttyMTD", - .write = mtdoops_console_write, - .setup = mtdoops_console_setup, - .unblank = mtdoops_console_sync, - .index = -1, - .data = &oops_cxt, -}; - -static int __init mtdoops_console_init(void) +static int __init mtdoops_init(void) { struct mtdoops_context *cxt = &oops_cxt; + int mtd_index; + char *endp; + if (strlen(mtddev) == 0) { + printk(KERN_ERR "mtdoops: mtd device must be supplied\n"); + return -EINVAL; + } if ((record_size & 4095) != 0) { printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); return -EINVAL; @@ -467,36 +423,41 @@ static int __init mtdoops_console_init(void) printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); return -EINVAL; } + + /* Setup the MTD device to use */ + cxt->name = mtddev; cxt->mtd_index = -1; + mtd_index = simple_strtoul(mtddev, &endp, 0); + if (endp != mtddev) + cxt->mtd_index = mtd_index; + cxt->oops_buf = vmalloc(record_size); if (!cxt->oops_buf) { printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n"); return -ENOMEM; } + memset(cxt->oops_buf, 0xff, record_size); - spin_lock_init(&cxt->writecount_lock); INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); - register_console(&mtdoops_console); register_mtd_user(&mtdoops_notifier); return 0; } -static void __exit mtdoops_console_exit(void) +static void __exit mtdoops_exit(void) { struct mtdoops_context *cxt = &oops_cxt; unregister_mtd_user(&mtdoops_notifier); - unregister_console(&mtdoops_console); kfree(cxt->name); vfree(cxt->oops_buf); vfree(cxt->oops_page_used); } -subsys_initcall(mtdoops_console_init); -module_exit(mtdoops_console_exit); +module_init(mtdoops_init); +module_exit(mtdoops_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Richard Purdie "); -- 1.6.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/