| === himcesjf_ is now known as him-cesjf | ||
| SysMan-One | Hello There! | 10:36 |
|---|---|---|
| * apw looks up | 10:36 | |
| SysMan-One | I have a question is related to the Block I/O. | 10:36 |
| SysMan-One | It's acceptable here or not ? | 10:36 |
| apw | i would ask and see what happens, as without more context i doubt i can tell if it is going to be off topic | 10:37 |
| SysMan-One | Ok. | 10:37 |
| SysMan-One | I working on filter-driver which is live on top of other block-device. | 10:38 |
| SysMan-One | I intercept READ/WRITE request to performs modifications of disk sectors before write to disk and before return to kernel. | 10:39 |
| apw | something like device-mapper then | 10:40 |
| SysMan-One | Right! The first question: I clonning oroginal BIO and buffers to be written to disk as follows: | 10:41 |
| SysMan-One | if ( !(*dst = bio_clone_bioset(src, gfp /* GFP_KERNEL */, src->bi_pool /* NULL*/)) ) | 10:42 |
| SysMan-One | { | 10:42 |
| SysMan-One | printk(KERN_ERR __MODULE__ ": bio_clone_bioset() -> NULL\n"); | 10:42 |
| SysMan-One | return-ENOMEM; | 10:42 |
| SysMan-One | } | 10:42 |
| SysMan-One | if ( status = bio_alloc_pages(*dst , GFP_KERNEL)) | 10:42 |
| SysMan-One | { | 10:42 |
| SysMan-One | printk(KERN_ERR __MODULE__ ": bio_alloc_pages() -> %d\n", status); | 10:42 |
| SysMan-One | returnstatus; | 10:42 |
| SysMan-One | } | 10:42 |
| SysMan-One | bio_copy_data(*dst, src); | 10:42 |
| SysMan-One | Is it correct way ? | 10:42 |
| SysMan-One | Sorry, forgot include header: | 10:43 |
| SysMan-One | static int __dua_bio_clone( | 10:43 |
| SysMan-One | struct bio*src, | 10:43 |
| SysMan-One | struct bio**dst | 10:43 |
| SysMan-One | ) | 10:43 |
| SysMan-One | { | 10:43 |
| SysMan-One | intstatus; | 10:43 |
| SysMan-One | gfp_tgfp = GFP_NOIO; //GFP_KERNEL; // (GFP_NOIO | __GFP_HIGH); | 10:43 |
| SysMan-One | So, is there someone who can help me to resolve question ? | 10:46 |
| apw | SysMan-One, i would look at what device-mapper does as it is likley the kind of framework you are becoming | 10:54 |
| apw | though why would you not make this a device-mapper personality in that case | 10:54 |
| SysMan-One | Thanks for you attention. A some task conditions prevents to use device-mapper way, it's not my choice. | 10:57 |
| apw | but as it is doing the same kind of things, it is likley got the right ways of doing things in it | 10:57 |
| apw | one of the encryption personalitys sounds closest | 10:58 |
| SysMan-One | I understand ... I cannot explain more about of the project, but u are right here, it's transparent en/de-cryption. | 10:59 |
| SysMan-One | Can i ask second question ? | 11:01 |
| apw | yep | 11:01 |
| SysMan-One | Ok. Thanks. | 11:01 |
| SysMan-One | I wrote "my_endio" routine to performs processing of the read disk blocks. I'll past some portions of code follows, ok ? | 11:04 |
| apw | better to pastebinit | 11:04 |
| SysMan-One | Hmmm ... It's about of 60-70 lines. | 11:04 |
| apw | right which is about 58 lines too much to paste in irc, as it comes out a one line per second and annoys everyone | 11:05 |
| SysMan-One | Ok. Will use pastebin and post the link. | 11:06 |
| SysMan-One | The piece of code which is supposed to process read disk blocks has been placed at the : https://pastebin.com/Pdyf4dNL | 11:13 |
| SysMan-One | May be I doing something wrong with iterators ? | 11:13 |
| apw | doesn't bio_copy_block do the sort of thing you are doing, so how it handles them (which seems different) might help | 11:23 |
| SysMan-One | I working under 4.4 and 4.15 kernels (Ubuntu 16) . I did not found "bio_copy_block" routine in the headers and sources. Do u mean something other ? | 11:27 |
| apw | in mainline kernel linus' tip it exists and looks like something you could use as a template | 11:28 |
| SysMan-One | bio_copy_data - works for me, my primary question is related to memory allocation: | 11:30 |
| SysMan-One | bio_clone_bioset(src, GFP_NOIO, src->bi_pool) - it's right usage ? | 11:30 |
| SysMan-One | using GFP_KERNEL in bio_alloc_pages(*dst , GFP_KERNEL) - is acceptable ? | 11:31 |
| SysMan-One | (yes, bio_copy_data I have used as template) - but why .bv_length is zero ?! | 11:33 |
| SysMan-One | Hello ! | 11:38 |
| SysMan-One | Can we off from main chatting or it will bother u ? | 11:38 |
| apw | sure | 11:39 |
| apw | in both cases you care about whether it is safe to block there | 12:11 |
| apw | what locks you have held etc, as to whether it is safe | 12:12 |
| apw | using NOIO seems logical as you are trying to do IO now, and if you | 12:12 |
| apw | cannot get enough memory to do _this_ io, trying to do io to free memory is no more likely to work | 12:12 |
| === SimonNL is now known as SimonNL_Afk | ||
| === SimonNL_Afk is now known as SimonNL | ||
| kees | apw: can I convince you to enable some kernel options? :) https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1783651 | 22:42 |
| ubot5 | Ubuntu bug 1783651 in linux (Ubuntu) "Please enable CONFIG_PAGE_POISONING" [Undecided,New] | 22:42 |
| tyhicks | kees (cc apw): thanks - I left a comment but I'm at my eod at this point so that's all I can do for now :) | 23:02 |
| kees | tyhicks: thanks! I don't want the sanity checking -- I think that's too heavy-duty for the general case. | 23:58 |
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