On 9/17/05, Sanjay Kumar, Noida <sanjayku@xxxxxxxxxxxxxxxxx> wrote: > > I am trying to implement a linux block device driver.And I have > >some doubts while understanding the drivers.I am listing them.Will you > >please help me. > > > >1.In the struct gendisk structure wht is the field > >int first_minor; > > refer to? > >is it the first partion number?wht is the partion number mean? > > first_minor denotes the starting minor device number for this gendisk. > For e.g. if you initialize first_minor with 5 and you create 2 > partitions on this disk, then the disk will have minor number 5 and the > two partitions will have minor number 6 and 7. This basically decides > how minor numbers are allocated. > I want to add one more example, that hda and hdb both have same major number which is 3 but the starting minor numbers of both devices are different means hda have first_minor=0 and minors=64, where as hdb has first_minor=64 and minors=64 So, hda starts with 3,0 to 3,63 and hdb with 3,64 to 3,127 > > > >and wht is the field minors refer to? > > "minors" refer to maximum number of partitions possible on the disk > > Please correct me if I am wrong. > > > > >and while implementing in a sample driver they are using > >dev->gd->first_minor = which*NUM_OF_MINORS; > >where gd is the reference to gendisk structure > >wht is the word 'which' refer to and in which file it is defined? > > > >i am using the > >set_capacity(dev->gd, nsectors*(hardsect_size/KERNEL_SECTOR_SIZE)); > >then > >and i am getting the error undefined symbol KERNEL_SECTOR_SIZE. > >where it is located. > > > > I think you missed to see in the start of the sbull (LDD3 sample) code that it is #define KERNEL_SECTOR_SIZE 512 -- Fawad Lateef -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
