drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare

The f_op->mmap interface is deprecated, so update the vmbus driver to use
its successor, mmap_prepare.

This updates all callbacks which referenced the function pointer
hv_mmap_ring_buffer to instead reference hv_mmap_prepare_ring_buffer,
utilising the newly introduced compat_set_desc_from_vma() and
__compat_vma_mmap() to be able to implement this change.

The UIO HV generic driver is the only user of hv_create_ring_sysfs(),
which is the only function which references
vmbus_channel->mmap_prepare_ring_buffer which, in turn, is the only
external interface to hv_mmap_prepare_ring_buffer.

This patch therefore updates this caller to use mmap_prepare instead,
which also previously used vm_iomap_memory(), so this change replaces it
with its mmap_prepare equivalent, mmap_action_simple_ioremap().

[akpm@linux-foundation.org: restore struct vmbus_channel comment, per Michael Kelley]
Link: https://lkml.kernel.org/r/05467cb62267d750e5c770147517d4df0246cda6.1774045440.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bodo Stroesser <bostroesser@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Hildenbrand <david@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Long Li <longli@microsoft.com>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Richard Weinberger <richard@nod.at>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 21 insertions, 14 deletions

diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 7bd8f8486e85..31f576464f18 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -545,8 +545,8 @@ static inline int hv_debug_add_dev_dir(struct hv_device *dev)
 
 /* Create and remove sysfs entry for memory mapped ring buffers for a channel */
 int hv_create_ring_sysfs(struct vmbus_channel *channel,
-			 int (*hv_mmap_ring_buffer)(struct vmbus_channel *channel,
-						    struct vm_area_struct *vma));
+			 int (*hv_mmap_prepare_ring_buffer)(struct vmbus_channel *channel,
+							    struct vm_area_desc *desc));
 int hv_remove_ring_sysfs(struct vmbus_channel *channel);
 
 #endif /* _HYPERV_VMBUS_H */
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index bc4fc1951ae1..45625487ba36 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1951,12 +1951,19 @@ static int hv_mmap_ring_buffer_wrapper(struct file *filp, struct kobject *kobj,
 				       struct vm_area_struct *vma)
 {
 	struct vmbus_channel *channel = container_of(kobj, struct vmbus_channel, kobj);
+	struct vm_area_desc desc;
+	int err;
 
 	/*
-	 * hv_(create|remove)_ring_sysfs implementation ensures that mmap_ring_buffer
-	 * is not NULL.
+	 * hv_(create|remove)_ring_sysfs implementation ensures that
+	 * mmap_prepare_ring_buffer is not NULL.
 	 */
-	return channel->mmap_ring_buffer(channel, vma);
+	compat_set_desc_from_vma(&desc, filp, vma);
+	err = channel->mmap_prepare_ring_buffer(channel, &desc);
+	if (err)
+		return err;
+
+	return __compat_vma_mmap(&desc, vma);
 }
 
 static struct bin_attribute chan_attr_ring_buffer = {
@@ -2048,13 +2055,13 @@ static const struct kobj_type vmbus_chan_ktype = {
 /**
  * hv_create_ring_sysfs() - create "ring" sysfs entry corresponding to ring buffers for a channel.
  * @channel: Pointer to vmbus_channel structure
- * @hv_mmap_ring_buffer: function pointer for initializing the function to be called on mmap of
+ * @hv_mmap_prepare_ring_buffer: function pointer for initializing the function to be called on mmap
  *                       channel's "ring" sysfs node, which is for the ring buffer of that channel.
  *                       Function pointer is of below type:
- *                       int (*hv_mmap_ring_buffer)(struct vmbus_channel *channel,
- *                                                  struct vm_area_struct *vma))
- *                       This has a pointer to the channel and a pointer to vm_area_struct,
- *                       used for mmap, as arguments.
+ *                       int (*hv_mmap_prepare_ring_buffer)(struct vmbus_channel *channel,
+ *                                                          struct vm_area_desc *desc))
+ *                       This has a pointer to the channel and a pointer to vm_area_desc,
+ *                       used for mmap_prepare, as arguments.
  *
  * Sysfs node for ring buffer of a channel is created along with other fields, however its
  * visibility is disabled by default. Sysfs creation needs to be controlled when the use-case
@@ -2071,12 +2078,12 @@ static const struct kobj_type vmbus_chan_ktype = {
  * Returns 0 on success or error code on failure.
  */
 int hv_create_ring_sysfs(struct vmbus_channel *channel,
-			 int (*hv_mmap_ring_buffer)(struct vmbus_channel *channel,
-						    struct vm_area_struct *vma))
+			 int (*hv_mmap_prepare_ring_buffer)(struct vmbus_channel *channel,
+							    struct vm_area_desc *desc))
 {
 	struct kobject *kobj = &channel->kobj;
 
-	channel->mmap_ring_buffer = hv_mmap_ring_buffer;
+	channel->mmap_prepare_ring_buffer = hv_mmap_prepare_ring_buffer;
 	channel->ring_sysfs_visible = true;
 
 	return sysfs_update_group(kobj, &vmbus_chan_group);
@@ -2098,7 +2105,7 @@ int hv_remove_ring_sysfs(struct vmbus_channel *channel)
 
 	channel->ring_sysfs_visible = false;
 	ret = sysfs_update_group(kobj, &vmbus_chan_group);
-	channel->mmap_ring_buffer = NULL;
+	channel->mmap_prepare_ring_buffer = NULL;
 	return ret;
 }
 EXPORT_SYMBOL_GPL(hv_remove_ring_sysfs);