Merge tag 'block-ioctl-cleanup-5.6' into 5.6/scsi-queue

Pull compat_ioctl cleanup from Arnd. Here's his description:

This series concludes the work I did for linux-5.5 on the compat_ioctl()
cleanup, killing off fs/compat_ioctl.c and block/compat_ioctl.c by moving
everything into drivers.

Overall this would be a reduction both in complexity and line count, but
as I'm also adding documentation the overall number of lines increases
in the end.

My plan was originally to keep the SCSI and block parts separate.
This did not work easily because of interdependencies: I cannot
do the final SCSI cleanup in a good way without first addressing the
CDROM ioctls, so this is one series that I hope could be merged through
either the block or the scsi git trees, or possibly both if you can
pull in the same branch.

The series comes in these steps:

1. clean up the sg v3 interface as suggested by Linus. I have
   talked about this with Doug Gilbert as well, and he would
   rebase his sg v4 patches on top of "compat: scsi: sg: fix v3
   compat read/write interface"

2. Actually moving handlers out of block/compat_ioctl.c and
   block/scsi_ioctl.c into drivers, mixed in with cleanup
   patches

3. Document how to do this right. I keep getting asked about this,
   and it helps to point to some documentation file.

The branch is based on another one that fixes a couple of bugs found
during the creation of this series.

Changes since v3:
  https://lore.kernel.org/lkml/20200102145552.1853992-1-arnd@arndb.de/

- Move sr_compat_ioctl fixup to correct patch (Ben Hutchings)
- Add Reviewed-by tags

Changes since v2:
  https://lore.kernel.org/lkml/20191217221708.3730997-1-arnd@arndb.de/

- Rebase to v5.5-rc4, which contains the earlier bugfixes
- Fix sr_block_compat_ioctl() error handling bug found by
  Ben Hutchings
- Fix idecd_locked_compat_ioctl() compat_ptr() bug
- Don't try to handle HDIO_DRIVE_TASKFILE in drivers/ide
- More documentation improvements

Changes since v1:
  https://lore.kernel.org/lkml/20191211204306.1207817-1-arnd@arndb.de/

- move out the bugfixes into a branch for itself
- clean up scsi sg driver further as suggested by Christoph Hellwig
- avoid some ifdefs by moving compat_ptr() out of asm/compat.h
- split out the blkdev_compat_ptr_ioctl function; bug spotted by
  Ben Hutchings
- Improve formatting of documentation

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 11 insertions, 12 deletions

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 0cc702a70a96..c363294b3bb9 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -19,6 +19,7 @@
 #include <linux/iova.h>
 #include <linux/irq.h>
 #include <linux/mm.h>
+#include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/scatterlist.h>
 #include <linux/vmalloc.h>
@@ -44,7 +45,6 @@ struct iommu_dma_cookie {
 		dma_addr_t		msi_iova;
 	};
 	struct list_head		msi_page_list;
-	spinlock_t			msi_lock;
 
 	/* Domain for flush queue callback; NULL if flush queue not in use */
 	struct iommu_domain		*fq_domain;
@@ -63,7 +63,6 @@ static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type)
 
 	cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
 	if (cookie) {
-		spin_lock_init(&cookie->msi_lock);
 		INIT_LIST_HEAD(&cookie->msi_page_list);
 		cookie->type = type;
 	}
@@ -399,7 +398,7 @@ static int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
 }
 
 static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
-		size_t size, dma_addr_t dma_limit, struct device *dev)
+		size_t size, u64 dma_limit, struct device *dev)
 {
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	struct iova_domain *iovad = &cookie->iovad;
@@ -424,7 +423,7 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
 	dma_limit = min_not_zero(dma_limit, dev->bus_dma_limit);
 
 	if (domain->geometry.force_aperture)
-		dma_limit = min(dma_limit, domain->geometry.aperture_end);
+		dma_limit = min(dma_limit, (u64)domain->geometry.aperture_end);
 
 	/* Try to get PCI devices a SAC address */
 	if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev))
@@ -477,7 +476,7 @@ static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr,
 }
 
 static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
-		size_t size, int prot, dma_addr_t dma_mask)
+		size_t size, int prot, u64 dma_mask)
 {
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
@@ -1176,7 +1175,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
 		if (msi_page->phys == msi_addr)
 			return msi_page;
 
-	msi_page = kzalloc(sizeof(*msi_page), GFP_ATOMIC);
+	msi_page = kzalloc(sizeof(*msi_page), GFP_KERNEL);
 	if (!msi_page)
 		return NULL;
 
@@ -1206,7 +1205,7 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
 	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
 	struct iommu_dma_cookie *cookie;
 	struct iommu_dma_msi_page *msi_page;
-	unsigned long flags;
+	static DEFINE_MUTEX(msi_prepare_lock); /* see below */
 
 	if (!domain || !domain->iova_cookie) {
 		desc->iommu_cookie = NULL;
@@ -1216,13 +1215,13 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
 	cookie = domain->iova_cookie;
 
 	/*
-	 * We disable IRQs to rule out a possible inversion against
-	 * irq_desc_lock if, say, someone tries to retarget the affinity
-	 * of an MSI from within an IPI handler.
+	 * In fact the whole prepare operation should already be serialised by
+	 * irq_domain_mutex further up the callchain, but that's pretty subtle
+	 * on its own, so consider this locking as failsafe documentation...
 	 */
-	spin_lock_irqsave(&cookie->msi_lock, flags);
+	mutex_lock(&msi_prepare_lock);
 	msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain);
-	spin_unlock_irqrestore(&cookie->msi_lock, flags);
+	mutex_unlock(&msi_prepare_lock);
 
 	msi_desc_set_iommu_cookie(desc, msi_page);