X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fmtd%2Fmtdoops.c;h=5a680e1e61f14dbc2ba684482792f2f40aabbee9;hb=771999b65f79264acde4b855e5d35696eca5e80c;hp=72c434c61b0a24f0aa43bd41755d66ce121abaa8;hpb=6ce0a856c10c8ab8568764436864616efa88e908;p=linux-2.6

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index 72c434c61b..5a680e1e61 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -28,11 +28,14 @@
 #include <linux/workqueue.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
 #include <linux/mtd/mtd.h>
 
 #define OOPS_PAGE_SIZE 4096
 
-struct mtdoops_context {
+static struct mtdoops_context {
 	int mtd_index;
 	struct work_struct work_erase;
 	struct work_struct work_write;
@@ -42,6 +45,9 @@ struct mtdoops_context {
 	int nextcount;
 
 	void *oops_buf;
+
+	/* writecount and disabling ready are spin lock protected */
+	spinlock_t writecount_lock;
 	int ready;
 	int writecount;
 } oops_cxt;
@@ -63,10 +69,7 @@ static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
 	erase.mtd = mtd;
 	erase.callback = mtdoops_erase_callback;
 	erase.addr = offset;
-	if (mtd->erasesize < OOPS_PAGE_SIZE)
-		erase.len = OOPS_PAGE_SIZE;
-	else
-		erase.len = mtd->erasesize;
+	erase.len = mtd->erasesize;
 	erase.priv = (u_long)&wait_q;
 
 	set_current_state(TASK_INTERRUPTIBLE);
@@ -182,10 +185,8 @@ badblock:
 	goto badblock;
 }
 
-static void mtdoops_workfunc_write(struct work_struct *work)
+static void mtdoops_write(struct mtdoops_context *cxt, int panic)
 {
-	struct mtdoops_context *cxt =
-			container_of(work, struct mtdoops_context, work_write);
 	struct mtd_info *mtd = cxt->mtd;
 	size_t retlen;
 	int ret;
@@ -194,7 +195,11 @@ static void mtdoops_workfunc_write(struct work_struct *work)
 		memset(cxt->oops_buf + cxt->writecount, 0xff,
 					OOPS_PAGE_SIZE - cxt->writecount);
 
-	ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
+	if (panic)
+		ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
+					OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
+	else
+		ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
 					OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
 
 	cxt->writecount = 0;
@@ -204,6 +209,15 @@ static void mtdoops_workfunc_write(struct work_struct *work)
 			cxt->nextpage * OOPS_PAGE_SIZE, retlen,	OOPS_PAGE_SIZE, ret);
 
 	mtdoops_inc_counter(cxt);
+}
+
+
+static void mtdoops_workfunc_write(struct work_struct *work)
+{
+	struct mtdoops_context *cxt =
+			container_of(work, struct mtdoops_context, work_write);
+
+	mtdoops_write(cxt, 0);
 }					
 
 static void find_next_position(struct mtdoops_context *cxt)
@@ -267,12 +281,18 @@ static void mtdoops_notify_add(struct mtd_info *mtd)
 		return;
 	}
 
+	if (mtd->erasesize < OOPS_PAGE_SIZE) {
+		printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
+				mtd->index);
+		return;
+	}
+
 	cxt->mtd = mtd;
 	cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
 
 	find_next_position(cxt);
 
-	printk(KERN_DEBUG "mtdoops: Attached to MTD device %d\n", mtd->index);
+	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 }
 
 static void mtdoops_notify_remove(struct mtd_info *mtd)
@@ -290,13 +310,28 @@ 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);
 
-	schedule_work(&cxt->work_write);
+	if (mtd->panic_write && in_interrupt())
+		/* Interrupt context, we're going to panic so try and log */
+		mtdoops_write(cxt, 1);
+	else
+		schedule_work(&cxt->work_write);
 }
 
 static void
@@ -304,6 +339,7 @@ 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();
@@ -313,6 +349,13 @@ mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 	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)
+		return;
+
 	if (cxt->writecount == 0) {
 		u32 *stamp = cxt->oops_buf;
 		*stamp = cxt->nextcount;
@@ -324,6 +367,11 @@ mtdoops_console_write(struct console *co, const char *s, unsigned int count)
 
 	memcpy(cxt->oops_buf + cxt->writecount, s, count);
 	cxt->writecount += count;
+
+	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
+
+	if (cxt->writecount == OOPS_PAGE_SIZE)
+		mtdoops_console_sync();
 }
 
 static int __init mtdoops_console_setup(struct console *co, char *options)
@@ -349,7 +397,6 @@ static struct console mtdoops_console = {
 	.write		= mtdoops_console_write,
 	.setup		= mtdoops_console_setup,
 	.unblank	= mtdoops_console_sync,
-	.flags		= CON_PRINTBUFFER,
 	.index		= -1,
 	.data		= &oops_cxt,
 };
@@ -362,7 +409,7 @@ static int __init mtdoops_console_init(void)
 	cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
 
 	if (!cxt->oops_buf) {
-		printk(KERN_ERR "Failed to allocate oops buffer workspace\n");
+		printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
 		return -ENOMEM;
 	}