Messages in this thread Patch in this message | | | Date | Sun, 31 Aug 2003 19:30:53 +0200 | From | Manfred Spraul <> | Subject | Re: [PATCH] Fix SMP support on 3c527 net driver |
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Felipe W Damasio wrote:
> Hi Manfred, > > Manfred Spraul wrote: > >> Additionally, you must replace the sleep_on calls with wait_event, or >> an open-coded wait queue: sleep_on is racy, it only works with cli(). > > > Oh, I didn't no that.. > >> IMHO the right way to fix cli() is >> - add a single spinlock to the driver or the device structure. Do not >> forget the spin_lock_init(). >> - replace cli/sti with spin_lock_irqsave/spin_unlock_irqsave. > > > Yes. > >> - Additionally acquire the spinlock in every interrupt handler (cli() >> stops all interrupts, spinlocks only stop interrupt on the current cpu). >> - check if there were recursive cli() calls. Fix them. >> - replace all sleep_on calls with wait queue calls. >> - check if there are any kmalloc or schedule calls in the area now >> under the spinlock, and reorganize the code. > > > But doesn't wait_queue call schedule()?
Yes, it does. You need a larger change to fix that. Something like the attached patch.
-- Manfred --- 2.6/drivers/net/3c527.c 2003-06-17 06:20:03.000000000 +0200 +++ build-2.6/drivers/net/3c527.c 2003-08-31 19:26:37.000000000 +0200 @@ -100,6 +100,7 @@ #include <linux/string.h> #include <linux/wait.h> #include <linux/ethtool.h> +#include <linux/spinlock.h> #include <asm/uaccess.h> #include <asm/system.h> @@ -179,6 +180,7 @@ u16 tx_ring_head; /* index to tx en-queue end */ u16 rx_ring_tail; /* index to rx de-queue end */ + spinlock_t lock; }; /* The station (ethernet) address prefix, used for a sanity check. */ @@ -579,6 +581,27 @@ return 0; } +/** + * wait_exec_pending - sleep until exec_pending reaches a certain value + * @lp: m32_local structure describing the target card + * @value: value to wait for + * + * The caller must acquire lp->lock before calling this function, it + * temporarily drops the lock when it sleeps. + */ + +static void wait_exec_pending(struct mc32_local *lp, int value) +{ + while (lp->exec_pending != value) { + DEFINE_WAIT(wait); + + prepare_to_wait(&lp->event, &wait, TASK_UNINTERRUPTIBLE); + spin_unlock_irq(&lp->lock); + schedule(); + finish_wait(&lp->event, &wait); + spin_lock_irq(&lp->lock); + } +} /** * mc32_command - send a command and sleep until completion @@ -619,14 +642,11 @@ int ret = 0; /* - * Wait for a command + * Wait until there are no more pending commands */ - save_flags(flags); - cli(); - - while(lp->exec_pending) - sleep_on(&lp->event); + spin_lock_irqsave(&lp->lock, flags); + wait_exec_pending(lp, 0); /* * Issue mine @@ -634,7 +654,7 @@ lp->exec_pending=1; - restore_flags(flags); + spin_unlock_irqrestore(&lp->lock, flags); lp->exec_box->mbox=0; lp->exec_box->mbox=cmd; @@ -645,13 +665,10 @@ while(!(inb(ioaddr+HOST_STATUS)&HOST_STATUS_CRR)); outb(1<<6, ioaddr+HOST_CMD); - save_flags(flags); - cli(); - - while(lp->exec_pending!=2) - sleep_on(&lp->event); + spin_lock_irqsave(&lp->lock, flags); + wait_exec_pending(lp, 2); lp->exec_pending=0; - restore_flags(flags); + spin_unlock_irqrestore(&lp->lock, flags); if(lp->exec_box->mbox&(1<<13)) ret = -1; | |