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From: Arnd Bergmann <arnd@arndb.de>
To: linux-kernel@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>, Dave Airlie <airlied@linux.ie>,
	dri-devel@lists.freedesktop.org
Subject: [PATCH 01/20] drm/i810: remove the BKL
Date: Tue, 25 Jan 2011 23:17:15 +0100	[thread overview]
Message-ID: <1295993854-4971-2-git-send-email-arnd@arndb.de> (raw)
In-Reply-To: <1295993854-4971-1-git-send-email-arnd@arndb.de>

SMP i810 systems were practically nonexistent and the configuration
was not officially supported by Intel at the time when Pentium-III
was common.

With this change, it is still possible to build a distribution kernel
that has support for SMP and includes the i810 driver without the BKL.
As a precaution, check for the theoretical SMP case at run time and
refuse to load the driver.

We also need to disable CONFIG_PREEMPT builds for this driver.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
---
 drivers/gpu/drm/Kconfig         |    4 ++--
 drivers/gpu/drm/i810/i810_dma.c |   18 +-----------------
 drivers/gpu/drm/i810/i810_drv.c |    6 +++++-
 3 files changed, 8 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index bea966f..9fc650d 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -73,8 +73,8 @@ source "drivers/gpu/drm/radeon/Kconfig"
 
 config DRM_I810
 	tristate "Intel I810"
-	# BKL usage in order to avoid AB-BA deadlocks, may become BROKEN_ON_SMP
-	depends on DRM && AGP && AGP_INTEL && BKL
+	# !PREEMPT because of missing ioctl locking
+	depends on DRM && AGP && AGP_INTEL && (!PREEMPT || BROKEN)
 	help
 	  Choose this option if you have an Intel I810 graphics card.  If M is
 	  selected, the module will be called i810.  AGP support is required
diff --git a/drivers/gpu/drm/i810/i810_dma.c b/drivers/gpu/drm/i810/i810_dma.c
index ff33e53..8f371e8 100644
--- a/drivers/gpu/drm/i810/i810_dma.c
+++ b/drivers/gpu/drm/i810/i810_dma.c
@@ -37,7 +37,6 @@
 #include <linux/interrupt.h>	/* For task queue support */
 #include <linux/delay.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/pagemap.h>
 
 #define I810_BUF_FREE		2
@@ -94,7 +93,6 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 	struct drm_buf *buf;
 	drm_i810_buf_priv_t *buf_priv;
 
-	lock_kernel();
 	dev = priv->minor->dev;
 	dev_priv = dev->dev_private;
 	buf = dev_priv->mmap_buffer;
@@ -104,7 +102,6 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 	vma->vm_file = filp;
 
 	buf_priv->currently_mapped = I810_BUF_MAPPED;
-	unlock_kernel();
 
 	if (io_remap_pfn_range(vma, vma->vm_start,
 			       vma->vm_pgoff,
@@ -116,7 +113,7 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 static const struct file_operations i810_buffer_fops = {
 	.open = drm_open,
 	.release = drm_release,
-	.unlocked_ioctl = i810_ioctl,
+	.unlocked_ioctl = drm_ioctl,
 	.mmap = i810_mmap_buffers,
 	.fasync = drm_fasync,
 	.llseek = noop_llseek,
@@ -1242,19 +1239,6 @@ int i810_driver_dma_quiescent(struct drm_device *dev)
 	return 0;
 }
 
-/*
- * call the drm_ioctl under the big kernel lock because
- * to lock against the i810_mmap_buffers function.
- */
-long i810_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	int ret;
-	lock_kernel();
-	ret = drm_ioctl(file, cmd, arg);
-	unlock_kernel();
-	return ret;
-}
-
 struct drm_ioctl_desc i810_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I810_INIT, i810_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY|DRM_UNLOCKED),
 	DRM_IOCTL_DEF_DRV(I810_VERTEX, i810_dma_vertex, DRM_AUTH|DRM_UNLOCKED),
diff --git a/drivers/gpu/drm/i810/i810_drv.c b/drivers/gpu/drm/i810/i810_drv.c
index 88bcd33..0152fa2 100644
--- a/drivers/gpu/drm/i810/i810_drv.c
+++ b/drivers/gpu/drm/i810/i810_drv.c
@@ -57,7 +57,7 @@ static struct drm_driver driver = {
 		 .owner = THIS_MODULE,
 		 .open = drm_open,
 		 .release = drm_release,
-		 .unlocked_ioctl = i810_ioctl,
+		 .unlocked_ioctl = drm_ioctl,
 		 .mmap = drm_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,
@@ -79,6 +79,10 @@ static struct drm_driver driver = {
 
 static int __init i810_init(void)
 {
+	if (num_possible_cpus() > 1) {
+		pr_err("drm/i810 does not support SMP\n");
+		return -EINVAL;
+	}
 	driver.num_ioctls = i810_max_ioctl;
 	return drm_init(&driver);
 }
-- 
1.7.1


  reply	other threads:[~2011-01-25 22:17 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-25 22:17 [RFC 00/20] Proposal for remaining BKL users Arnd Bergmann
2011-01-25 22:17 ` Arnd Bergmann
2011-01-25 22:17 ` Arnd Bergmann [this message]
2011-01-25 22:17 ` [PATCH 02/20] drm: remove i830 driver Arnd Bergmann
2011-01-25 22:17 ` [PATCH 03/20] staging/usbip: convert to kthread Arnd Bergmann
2011-01-28 17:53   ` Max Vozeler
2011-01-28 18:48     ` Arnd Bergmann
2011-03-01 22:15     ` Arnd Bergmann
2011-01-25 22:17 ` [PATCH 04/20] staging/cx25721: serialize access to devlist Arnd Bergmann
2011-01-26 16:23   ` Palash Bandyopadhyay
2011-01-31 21:37   ` Greg KH
2011-01-25 22:17 ` [PATCH 05/20] staging/go7007: remove the BKL Arnd Bergmann
2011-01-25 22:17 ` [PATCH 06/20] staging: Remove autofs3 Arnd Bergmann
2011-01-26  7:41   ` H. Peter Anvin
2011-01-25 22:17 ` [PATCH 07/20] staging: remove smbfs Arnd Bergmann
2011-01-25 22:17 ` [PATCH 08/20] adfs: remove the big kernel lock Arnd Bergmann
2011-01-25 22:20   ` Russell King
2011-01-25 22:17 ` [PATCH 09/20] hpfs: rename big kernel lock to hpfs_lock Arnd Bergmann
2011-01-25 22:17 ` [PATCH 10/20] hpfs: replace BKL with a global mutex Arnd Bergmann
2011-01-26  0:15   ` Andi Kleen
2011-01-26  0:19   ` Andi Kleen
2011-01-26 12:48     ` [PATCH v2] hpfs: remove the BKL Arnd Bergmann
2011-01-26 12:50     ` [PATCH 10/20] hpfs: replace BKL with a global mutex Arnd Bergmann
2011-01-26 16:52       ` Andi Kleen
2011-01-27  5:01         ` Nick Piggin
2011-01-27 10:57           ` Miklos Szeredi
2011-01-25 22:17 ` [PATCH 11/20] hpfs: move to drivers/staging Arnd Bergmann
2011-02-07 16:17   ` Mikulas Patocka
2011-02-07 19:31     ` Arnd Bergmann
2011-01-25 22:17 ` [PATCH 12/20] x25: remove the BKL Arnd Bergmann
2011-01-27 10:07   ` Andrew Hendry
2011-01-27 12:17     ` Arnd Bergmann
2011-01-27 12:38       ` [PATCH v2] " Arnd Bergmann
2011-01-27 13:20         ` Eric Dumazet
2011-01-27 13:43           ` Arnd Bergmann
2011-01-25 22:17 ` [PATCH 13/20] appletalk: move to staging Arnd Bergmann
2011-01-25 22:17 ` [PATCH 14/20] staging/appletalk: remove the BKL Arnd Bergmann
2011-01-25 22:29   ` David Miller
2011-01-26 12:57     ` Arnd Bergmann
2011-01-25 22:17 ` [PATCH 15/20] ufs: " Arnd Bergmann
2011-01-26  2:30   ` Nick Bowler
2011-01-26 12:53     ` Arnd Bergmann
2011-01-27  5:47   ` Nick Piggin
2011-01-27 13:13     ` Arnd Bergmann
2011-01-25 22:17 ` [PATCH 16/20] ipx: " Arnd Bergmann
2011-01-25 22:17 ` [PATCH 17/20] tracing: don't trace " Arnd Bergmann
2011-01-25 22:28   ` Frederic Weisbecker
2011-01-25 22:17 ` [PATCH 18/20] rtmutex-tester: remove BKL tests Arnd Bergmann
2011-01-26 15:00   ` [tip:core/locking] rtmutex-tester: Remove " tip-bot for Arnd Bergmann
2011-02-22 20:57   ` [tip:irq/core] rtmutex: tester: " tip-bot for Arnd Bergmann
2011-01-25 22:17 ` [PATCH 19/20] drivers: remove extraneous includes of smp_lock.h Arnd Bergmann
2011-01-25 22:17 ` [PATCH 20/20] BKL: That's all, folks Arnd Bergmann
2011-01-26  6:19   ` Ingo Molnar
2011-01-26  8:47     ` Alan Cox
2011-01-26 11:01       ` Ingo Molnar
2011-01-26 11:22   ` Thomas Gleixner
2011-01-26  2:22 ` [RFC 00/20] Proposal for remaining BKL users Greg KH
2011-01-26  2:22   ` Greg KH
2011-01-26 11:31   ` Arnd Bergmann
2011-01-26 11:31     ` Arnd Bergmann
2011-01-26 11:58     ` Mauro Carvalho Chehab
2011-01-26 13:45       ` Arnd Bergmann
2011-01-26 13:45         ` Arnd Bergmann
2011-01-26 16:24         ` Palash Bandyopadhyay

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