From: Boaz Harrosh Date: Sun, 25 Jan 2009 14:58:03 +0000 (+0200) Subject: [SCSI] osd_uld: API for retrieving osd devices from Kernel X-Git-Tag: v2.6.30-rc1~641^2~91 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b799bc7da0ce5ba4a988c521a8fb10452eb419f0;p=pandora-kernel.git [SCSI] osd_uld: API for retrieving osd devices from Kernel Kernel clients like exofs can retrieve struct osd_dev(s) by means of below API. + osduld_path_lookup() - given a path (e.g "/dev/osd0") locks and returns the corresponding struct osd_dev, which is then needed for subsequent libosd use. + osduld_put_device() - free up use of an osd_dev. Devices can be shared by multiple clients. The osd_uld_device's life time is governed by an embedded kref structure. The osd_uld_device holds an extra reference to both it's char-device and it's scsi_device, and will release these just before the final deallocation. There are three possible lock sources of the osd_uld_device 1. First and for most is the probe() function called by scsi-ml upon a successful login into a target. Released in release() when logout. 2. Second by user-mode file handles opened on the char-dev. 3. Third is here by Kernel users. All three locks must be removed before the osd_uld_device is freed. The MODULE has three lock sources as well: 1. scsi-ml at probe() time, removed after release(). (login/logout) 2. The user-mode file handles open/close. 3. Import symbols by client modules like exofs. TODO: This API is not enough for the pNFS-objects LD. A more versatile API will be needed. Proposed API could be: struct osd_dev *osduld_sysid_lookup(const char id[OSD_SYSTEMID_LEN]); Signed-off-by: Boaz Harrosh Signed-off-by: James Bottomley --- Reading git-diff-tree failed