Simple Read operation on a misc device driver
For the Eudyptula's Chanllenge Task 6, i need to write a misc device driver with simple read/write operations. The following was the answer to part of my code:
static char eid[] = EUDYPTULAID;
static ssize_t misc_device_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { if (*ppos == sizeof(eid)) return 0; else if (*ppos != 0 || count < sizeof(eid)) return -EINVAL;
if (copy_to_user(buf, eid, sizeof(eid))) return -EINVAL;
*ppos = sizeof(eid);
return *ppos; }
This whole function can be made much more "simple" and reduced to one single line {hint} (It's just a "simple" function call {hint}). Anyone know that "single" function?
On Fri, Apr 18, 2014 at 06:30:44PM -0300, Aldo Esteban Paz wrote:
For the Eudyptula's Chanllenge Task 6, i need to write a misc device driver with simple read/write operations. The following was the answer to part of my code:
static char eid[] = EUDYPTULAID;
static ssize_t misc_device_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { if (*ppos == sizeof(eid)) return 0; else if (*ppos != 0 || count < sizeof(eid)) return -EINVAL;
if (copy_to_user(buf, eid, sizeof(eid))) return -EINVAL;
*ppos = sizeof(eid);
return *ppos; }
This whole function can be made much more "simple" and reduced to one single line {hint} (It's just a "simple" function call {hint}).
Anyone know that "single" function?
Yes, but you really should do your own research for stuff like this, that's what the challenge is all about, not asking others to do it for you :(
On Fri, Apr 18, 2014 at 02:35:53PM -0700, Greg KH wrote:
On Fri, Apr 18, 2014 at 06:30:44PM -0300, Aldo Esteban Paz wrote:
For the Eudyptula's Chanllenge Task 6, i need to write a misc device driver with simple read/write operations. The following was the answer to part of my code:
static char eid[] = EUDYPTULAID;
static ssize_t misc_device_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { if (*ppos == sizeof(eid)) return 0; else if (*ppos != 0 || count < sizeof(eid)) return -EINVAL;
if (copy_to_user(buf, eid, sizeof(eid))) return -EINVAL;
*ppos = sizeof(eid);
return *ppos; }
This whole function can be made much more "simple" and reduced to one single line {hint} (It's just a "simple" function call {hint}).
Anyone know that "single" function?
Yes, but you really should do your own research for stuff like this, that's what the challenge is all about, not asking others to do it for you :(
I'm curious about this. I didn't get the simple, one-line function call feedback and my task was accepted with a regular function definition, similar to the one from the OP. -- L. Alberto Giménez GnuPG key ID 0xDD4E27AB
El 19/04/2014 18:52, "L. Alberto Giménez" <agimenez@sysvalve.es> escribió:
On Fri, Apr 18, 2014 at 02:35:53PM -0700, Greg KH wrote:
On Fri, Apr 18, 2014 at 06:30:44PM -0300, Aldo Esteban Paz wrote:
For the Eudyptula's Chanllenge Task 6, i need to write a misc device driver with simple read/write operations. The following was the answer to part of my code:
static char eid[] = EUDYPTULAID;
static ssize_t misc_device_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { if (*ppos == sizeof(eid)) return 0; else if (*ppos != 0 || count < sizeof(eid)) return -EINVAL;
if (copy_to_user(buf, eid, sizeof(eid))) return -EINVAL;
*ppos = sizeof(eid);
return *ppos; }
This whole function can be made much more "simple" and reduced to one single line {hint} (It's just a "simple" function call {hint}).
Anyone know that "single" function?
Yes, but you really should do your own research for stuff like this, that's what the challenge is all about, not asking others to do it for you :(
I'm curious about this. I didn't get the simple, one-line function call
feedback and
my task was accepted with a regular function definition, similar to the one from the OP.
That feedback may come in the next tasks ;)
-- L. Alberto Giménez GnuPG key ID 0xDD4E27AB
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participants (4)
-
Aldo Esteban Paz -
Fernando Apesteguía -
Greg KH -
L. Alberto Giménez