devfs: translate partition offsets in B_TRIM_DEVICE

Fixes bfs part of #10336. Untested on SATA (don't have a testing drive
to sacrifice) but working fine on SD/MMC.

This requires moving the copy from kernel to userland into the devfs. As
a result the code in the disk drivers becomes a bit simpler.

Also add some documentation for the common ioctls to implement for a
disk device.

Change-Id: Ie84b6a1d293828d33902a64b3c9d4b19aa6eacb1
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3640
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>

docs/develop/drivers/disk/ioctls.txt

@@ -0,0 +1,42 @@
+Here is a list of ioctls usually implemented by disk devices.
+
+B_GET_DEVICE_SIZE
+
+The parameter is a size_t and is filled with the disk size in bytes.
+This is limited to 4GB and not very useful. B_GET_GEOMETRY is used instead.
+
+B_GET_GEOMETRY
+
+The parameter is a device_geometry structure to be filled with the device geometry.
+
+B_GET_ICON_NAME
+
+Deprecated. Get the name of an icon to use. The icons are hardcoded in Tracker.
+
+B_GET_VECTOR_ICON
+
+The parameter is a device_icon structure to be populated with the icon data in HVIF format.
+This icon is then used to show the disk in Tracker, for example.
+
+B_EJECT_DEVICE
+
+Eject the device (for removable devices).
+
+B_LOAD_MEDIA
+
+Load the device (reverse of eject) if possible.
+
+B_FLUSH_DRIVE_CACHE
+
+Make sure all data is stored on persistent storage and not in caches (including any caching inside
+the device)
+
+B_TRIM_DEVICE
+
+The parameter is an fs_trim_data structure. It is guaranteed to be in kernel memory because
+the partition manager pre-processes requests coming from userland and makes sure no sectors
+are outside the partition range for a specific partition device.
+
+Mark the listed areas on disk as unused, allowing future reads to these areas to return
+random data or read errors. Flash memory devices (SSD, MMC, ...) may use this information
+to optimize their internal storage.

headers/os/drivers/Drivers.h

@@ -175,8 +175,8 @@ typedef struct {
 	uint32	range_count;
 	uint64	trimmed_size;			/* filled on return */
 	struct range {
-		uint64	offset;				/* offset (in bytes) */
-		uint64	size;
+		off_t	offset;				/* offset (in bytes) */
+		off_t	size;
 	} ranges[1];
 } fs_trim_data;
 

src/add-ons/kernel/drivers/disk/scsi/scsi_disk/scsi_disk.cpp

@@ -418,18 +418,10 @@ das_ioctl(void* cookie, uint32 op, void* buffer, size_t length)
 #if 0
 		case B_TRIM_DEVICE:
 		{
-			fs_trim_data* trimData;
-			MemoryDeleter deleter;
-			status_t status = get_trim_data_from_user(buffer, length, deleter,
-				trimData);
-			if (status != B_OK)
-				return status;
-
-			status = trim_device(info, trimData);
-			if (status != B_OK)
-				return status;
-
-			return copy_trim_data_to_user(buffer, trimData);
+			// We know the buffer is kernel-side because it has been
+			// preprocessed in devfs
+			ASSERT(IS_KERNEL_ADDRESS(buffer));
+			return trim_device(info, (fs_trim_data*)buffer);
 		}
 #endif
 

src/add-ons/kernel/drivers/disk/virtual/ram_disk/ram_disk.cpp

@@ -1474,18 +1474,10 @@ ram_disk_raw_device_control(void* _cookie, uint32 op, void* buffer,
 
 		case B_TRIM_DEVICE:
 		{
-			fs_trim_data* trimData;
-			MemoryDeleter deleter;
-			status_t status = get_trim_data_from_user(buffer, length, deleter,
-				trimData);
-			if (status != B_OK)
-				return status;
-
-			status = device->Trim(trimData);
-			if (status != B_OK)
-				return status;
-
-			return copy_trim_data_to_user(buffer, trimData);
+			// We know the buffer is kernel-side because it has been
+			// preprocessed in devfs
+			ASSERT(IS_KERNEL_ADDRESS(buffer));
+			return device->Trim((fs_trim_data*)buffer);
 		}
 
 		case RAM_DISK_IOCTL_INFO:

src/system/kernel/device_manager/devfs.cpp

@@ -33,6 +33,7 @@
 #include <lock.h>
 #include <Notifications.h>
 #include <util/AutoLock.h>
+#include <util/fs_trim_support.h>
 #include <vfs.h>
 #include <vm/vm.h>
 #include <wait_for_objects.h>
@@ -493,14 +494,14 @@ err1:
 }
 
 
-static inline void
+template<typename size_type> static inline void
 translate_partition_access(devfs_partition* partition, off_t& offset,
-	size_t& size)
+	size_type& size)
 {
 	ASSERT(offset >= 0);
 	ASSERT(offset < partition->info.size);
 
-	size = (size_t)min_c((off_t)size, partition->info.size - offset);
+	size = (size_type)min_c((off_t)size, partition->info.size - offset);
 	offset += partition->info.offset;
 }
 
@@ -1214,7 +1215,8 @@ devfs_read(fs_volume* _volume, fs_vnode* _vnode, void* _cookie, off_t pos,
 		if (pos >= vnode->stream.u.dev.partition->info.size)
 			return B_BAD_VALUE;
 
-		translate_partition_access(vnode->stream.u.dev.partition, pos, *_length);
+		translate_partition_access(vnode->stream.u.dev.partition, pos,
+			*_length);
 	}
 
 	if (*_length == 0)
@@ -1246,7 +1248,8 @@ devfs_write(fs_volume* _volume, fs_vnode* _vnode, void* _cookie, off_t pos,
 		if (pos >= vnode->stream.u.dev.partition->info.size)
 			return B_BAD_VALUE;
 
-		translate_partition_access(vnode->stream.u.dev.partition, pos, *_length);
+		translate_partition_access(vnode->stream.u.dev.partition, pos,
+			*_length);
 	}
 
 	if (*_length == 0)
@@ -1460,6 +1463,39 @@ devfs_ioctl(fs_volume* _volume, fs_vnode* _vnode, void* _cookie, uint32 op,
 				return user_memcpy(buffer, &geometry, sizeof(device_geometry));
 			}
 
+			case B_TRIM_DEVICE:
+			{
+				struct devfs_partition* partition
+					= vnode->stream.u.dev.partition;
+
+				fs_trim_data* trimData;
+				MemoryDeleter deleter;
+				status_t status = get_trim_data_from_user(buffer, length,
+					deleter, trimData);
+				if (status != B_OK)
+					return status;
+
+				if (partition != NULL) {
+					// If there is a partition, offset all ranges according
+					// to the partition start.
+					for (uint32 i = 0; i < trimData->range_count; i++) {
+						translate_partition_access(partition,
+							trimData->ranges[i].offset,
+							trimData->ranges[i].size);
+					}
+				}
+
+				status = vnode->stream.u.dev.device->Control(
+					cookie->device_cookie, op, trimData, length);
+
+				// Copy the data back to userland (it contains the number of
+				// trimmed bytes)
+				if (status == B_OK)
+					status = copy_trim_data_to_user(buffer, trimData);
+
+				return status;
+			}
+
 			case B_GET_DRIVER_FOR_DEVICE:
 			{
 #if 0