Messages in this thread | | | Subject | Re: [PATCH] fs: add FD_CLOFORK and O_CLOFORK | From | Eric Dumazet <> | Date | Sat, 07 May 2011 08:06:34 +0200 |
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Le samedi 07 mai 2011 à 12:49 +0800, Changli Gao a écrit :
> > for (i = open_files; i != 0; i--) { > struct file *f = *old_fds++; > if (f) { > - get_file(f); > + if (FD_ISSET(open_files - i, new_fdt->close_on_fork)) { > + FD_CLR(open_files - i, new_fdt->open_fds); > + f = NULL; > + } else { > + get_file(f); > + } > } else { > /*
You should change the main loop to
for (i = 0; i < open_files; i++) { struct file *f = *old_fds++;
if (f && FD_ISSET(i, new_fdt->close_on_fork)) f = NULL; if (f) get_file(f); else FD_CLR(i, new_fdt->open_fds) rcu_assign_pointer(*new_fds++, f); }
BTW the rcu_assign_pointer() is not necessary here, since we are the only thread populating new_fds at this point.
spin_unlock(&oldf->file_lock); and rcu_assign_pointer(newf->fdt, new_fdt); make sure once new_fds is visible to other threads, all our memory writes are committed.
sparse even warns us ;)
fs/file.c:371:3: warning: incorrect type in assignment (different address spaces) fs/file.c:371:3: expected struct file *<noident> fs/file.c:371:3: got struct file [noderef] <asn:4>*<noident>
I'll submit a patch in a separate thread
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